| Time | Measured pH | Calculated pH |
|---|---|---|
| 1988-10-31 | 8.1097 | |
| 1988-12-02 | 8.1092 | |
| 1989-01-08 | 8.1168 | |
| 1989-02-26 | 8.1316 | |
| 1989-03-27 | 8.1218 | |
| 1989-05-18 | 8.1158 | |
| 1989-06-24 | 8.1018 | |
| 1989-07-29 | 8.0991 | |
| 1989-08-24 | 8.093 | |
| 1989-09-22 | 8.099 | |
| 1989-09-18 | 8.0858 | |
| 1989-11-27 | 8.1101 | |
| 1990-01-05 | 8.1332 | |
| 1990-02-15 | 8.1229 | |
| 1990-03-19 | 8.134 | |
| 1990-04-13 | 8.1229 | |
| 1990-05-09 | 8.1167 | |
| 1990-06-13 | 8.1232 | |
| 1990-07-25 | 8.1084 | |
| 1990-09-14 | 8.085 | |
| 1990-11-19 | ||
| 1990-12-18 | 8.1212 | |
| 1991-02-03 | 8.1256 | |
| 1991-03-07 | 8.1263 | |
| 1991-04-10 | 8.1231 | |
| 1991-05-08 | 8.1144 | |
| 1991-06-05 | 8.1139 | |
| 1991-07-10 | 8.112 | |
| 1991-08-10 | 8.0992 | |
| 1991-09-18 | 8.0943 | |
| 1991-10-21 | 8.0981 | |
| 1991-12-07 | 8.104 | |
| 1992-01-05 | 8.1177 | |
| 1992-02-15 | 8.1256 | |
| 1992-03-06 | 8.119 | |
| 1992-04-17 | 8.107 | 8.1099 |
| 1992-06-09 | 8.087 | 8.1152 |
| 1992-07-05 | 8.091 | 8.0977 |
| 1992-08-05 | 8.095 | 8.0956 |
| 1992-09-23 | 8.093 | 8.0933 |
| 1992-10-20 | 8.087 | |
| 1992-11-24 | 8.099 | 8.1052 |
| 1992-12-16 | 8.106 | 8.1161 |
| 1993-01-20 | 8.122 | 8.1349 |
| 1993-02-17 | 8.115 | 8.1325 |
| 1993-04-15 | 8.111 | 8.1074 |
| 1993-05-21 | 8.114 | 8.1105 |
| 1993-07-26 | ||
| 1993-09-15 | 8.0802 | |
| 1993-10-30 | 8.105 | 8.094 |
| 1994-01-20 | 8.1508 | |
| 1994-02-17 | 8.1357 | |
| 1994-03-09 | 8.1204 | |
| 1994-06-19 | 8.1021 | |
| 1994-07-25 | 8.095 | 8.0858 |
| 1994-08-30 | 8.092 | 8.0883 |
| 1994-09-23 | 8.089 | 8.0875 |
| 1994-10-15 | 8.087 | 8.088 |
| 1994-11-19 | 8.103 | 8.1048 |
| 1995-02-06 | 8.112 | 8.1099 |
| 1995-03-04 | 8.113 | 8.1171 |
| 1995-04-06 | 8.103 | 8.1038 |
| 1995-05-07 | 8.111 | 8.1149 |
| 1995-07-30 | 8.086 | 8.0937 |
| 1995-08-29 | 8.087 | 8.0933 |
| 1995-09-26 | 8.075 | 8.0886 |
| 1995-10-27 | 8.089 | 8.0997 |
| 1995-11-17 | 8.097 | 8.1135 |
| 1996-01-17 | 8.104 | 8.1074 |
| 1996-03-27 | 8.114 | 8.1122 |
| 1996-04-24 | 8.106 | 8.1066 |
| 1996-05-22 | 8.09 | 8.0946 |
| 1996-06-26 | 8.078 | 8.0902 |
| 1996-07-27 | 8.084 | 8.0889 |
| 1996-08-21 | 8.078 | 8.0829 |
| 1996-10-02 | 8.084 | 8.0836 |
| 1996-10-30 | 8.091 | 8.0924 |
| 1996-12-11 | 8.113 | 8.1014 |
| 1997-01-08 | 8.115 | 8.1102 |
| 1997-02-18 | 8.088 | 8.0856 |
| 1997-03-12 | 8.092 | 8.1138 |
| 1997-04-09 | 8.088 | 8.1155 |
| 1997-05-07 | 8.1 | 8.101 |
| 1997-06-04 | 8.101 | 8.1058 |
| 1997-07-09 | 8.091 | 8.0895 |
| 1997-08-02 | 8.086 | 8.089 |
| 1997-09-25 | 8.08 | 8.0805 |
| 1997-12-05 | 8.107 | 8.1083 |
| 1998-01-11 | 8.111 | 8.1097 |
| 1998-02-19 | 8.117 | 8.1135 |
| 1998-03-18 | 8.101 | 8.1044 |
| 1998-04-15 | 8.109 | 8.1078 |
| 1998-05-13 | 8.111 | 8.105 |
| 1998-06-17 | 8.096 | 8.0937 |
| 1998-07-15 | 8.0805 | |
| 1998-08-10 | 8.0818 | |
| 1998-09-28 | 8.076 | |
| 1998-10-19 | 8.0818 | |
| 1998-11-11 | 8.0825 | |
| 1998-12-09 | 8.0948 | |
| 1999-01-13 | 8.0895 | |
| 1999-02-18 | 8.0997 | |
| 1999-03-17 | 8.135 | |
| 1999-04-14 | 8.123 | |
| 1999-05-10 | 8.1 | |
| 1999-07-14 | 8.0938 | |
| 1999-08-13 | 8.0759 | |
| 1999-10-15 | 8.0711 | |
| 1999-11-09 | 8.0824 | |
| 1999-12-15 | 8.0818 | |
| 2000-02-03 | 8.0966 | |
| 2000-03-01 | 8.0946 | |
| 2000-03-29 | 8.0942 | |
| 2000-04-26 | 8.0941 | |
| 2000-05-25 | 8.0677 | |
| 2000-06-21 | 8.0831 | |
| 2000-07-26 | 8.0872 | |
| 2000-08-23 | 8.0827 | |
| 2000-10-18 | 8.0678 | |
| 2000-11-30 | 8.095 | |
| 2000-12-20 | 8.0922 | |
| 2001-01-17 | 8.0929 | |
| 2001-02-14 | 8.0881 | |
| 2001-03-21 | 8.0894 | |
| 2001-04-18 | 8.0938 | |
| 2001-05-16 | 8.0948 | |
| 2001-06-14 | 8.0984 | |
| 2001-07-11 | 8.0857 | |
| 2001-08-08 | 8.0757 | |
| 2001-10-02 | 8.068 | |
| 2001-10-23 | 8.0885 | |
| 2001-11-17 | 8.0814 | |
| 2001-12-14 | 8.0925 | |
| 2002-01-16 | 8.0959 | |
| 2002-02-21 | 8.108 | |
| 2002-03-13 | 8.1085 | |
| 2002-05-21 | 8.0811 | |
| 2002-06-29 | 8.071 | |
| 2002-08-28 | 8.0706 | |
| 2002-10-07 | 8.0862 | |
| 2002-11-04 | 8.0876 | |
| 2002-11-25 | 8.0876 | |
| 2002-12-19 | 8.0937 | |
| 2003-01-17 | 8.1025 | |
| 2003-02-26 | 8.104 | |
| 2003-03-29 | 8.1016 | |
| 2003-04-24 | 8.0963 | |
| 2003-05-21 | 8.0905 | |
| 2003-06-20 | 8.083 | 8.0824 |
| 2003-07-20 | 8.065 | 8.0777 |
| 2003-08-21 | 8.071 | 8.0829 |
| 2003-10-15 | 8.083 | 8.0873 |
| 2003-11-10 | 8.083 | 8.0884 |
| 2003-12-20 | 8.107 | 8.1134 |
| 2004-01-22 | 8.103 | 8.0967 |
| 2004-02-25 | 8.097 | 8.1096 |
| 2004-03-20 | 8.114 | 8.1244 |
| 2004-04-21 | 8.094 | 8.0988 |
| 2004-05-19 | 8.083 | 8.0878 |
| 2004-06-16 | 8.081 | 8.0852 |
| 2004-07-13 | 8.079 | 8.0701 |
| 2004-08-16 | 8.078 | 8.071 |
| 2004-09-29 | 8.078 | 8.0705 |
| 2004-10-31 | 8.08 | 8.0836 |
| 2004-11-28 | 8.094 | 8.0898 |
| 2004-12-21 | 8.094 | 8.0992 |
| 2005-02-02 | 8.1 | 8.0963 |
| 2005-03-05 | 8.104 | 8.1065 |
| 2005-05-18 | 8.084 | 8.0899 |
| 2005-06-15 | 8.083 | 8.0809 |
| 2005-07-17 | 8.076 | 8.0664 |
| 2005-08-14 | 8.075 | 8.0751 |
| 2005-09-10 | 8.078 | 8.0601 |
| 2005-10-09 | 8.08 | 8.0777 |
| 2005-11-12 | 8.088 | 8.0843 |
| 2005-12-13 | 8.092 | 8.0888 |
| 2006-01-25 | 8.095 | 8.1135 |
| 2006-02-15 | 8.097 | 8.0953 |
| 2006-03-10 | 8.101 | 8.1084 |
| 2006-04-02 | 8.109 | 8.104 |
| 2006-05-27 | 8.086 | 8.0901 |
| 2006-06-14 | 8.076 | 8.0646 |
| 2006-07-13 | 8.076 | 8.0804 |
| 2006-08-09 | 8.079 | 8.0723 |
| 2006-09-16 | 8.069 | 8.077 |
| 2006-10-21 | 8.07 | 8.0679 |
| 2006-11-09 | 8.069 | 8.0772 |
| 2006-12-10 | 8.089 | 8.0908 |
| 2007-02-07 | 8.1 | 8.1047 |
| 2007-03-21 | 8.098 | 8.0973 |
| 2007-05-05 | 8.083 | 8.0808 |
| 2007-06-10 | ||
| 2007-07-08 | 8.076 | 8.0631 |
| 2007-08-04 | 8.07 | 8.066 |
| 2007-09-03 | 8.059 | 8.0616 |
| 2007-10-03 | 8.065 | 8.0639 |
| 2007-12-02 | 8.085 | 8.0678 |
| 2007-12-21 | 8.08 | 8.0856 |
| 2008-01-30 | 8.097 | 8.0957 |
| 2008-02-24 | 8.082 | 8.0957 |
| 2008-05-28 | 8.072 | 8.0694 |
| 2008-06-26 | 8.075 | 8.0735 |
| 2008-07-27 | 8.063 | 8.0635 |
| 2008-08-17 | 8.07 | 8.0729 |
| 2008-10-11 | 8.082 | 8.0799 |
| 2008-12-01 | 8.085 | 8.0816 |
| 2008-12-15 | ||
| 2009-01-21 | 8.098 | 8.0996 |
| 2009-02-18 | 8.101 | 8.1084 |
| 2009-04-29 | 8.089 | 8.0898 |
| 2009-05-28 | 8.07 | 8.0693 |
| 2009-07-04 | 8.059 | 8.0676 |
| 2009-07-25 | 8.056 | 8.0584 |
| 2009-08-19 | 8.057 | 8.0614 |
| 2009-09-25 | 8.057 | 8.0541 |
| 2009-11-04 | 8.06 | 8.0667 |
| 2009-12-10 | 8.074 | 8.0801 |
| 2010-02-15 | ||
| 2010-03-10 | 8.092 | 8.0969 |
| 2010-04-07 | 8.088 | 8.0968 |
| 2010-05-19 | 8.075 | 8.0839 |
| 2010-06-09 | 8.063 | 8.0688 |
| 2010-07-09 | 8.064 | 8.0703 |
| 2010-08-08 | 8.066 | 8.0785 |
| 2010-09-04 | 8.066 | 8.0691 |
| 2010-10-04 | 8.066 | 8.0651 |
| 2010-11-21 | 8.075 | 8.0715 |
| 2011-01-09 | ||
| 2011-01-29 | 8.086 | 8.0891 |
| 2011-03-01 | 8.082 | 8.0918 |
| 2011-04-12 | 8.084 | 8.0885 |
| 2011-05-10 | 8.081 | 8.0797 |
| 2011-07-20 | 8.074 | 8.0696 |
| 2011-08-30 | 8.078 | 8.0717 |
| 2011-09-27 | 8.074 | 8.0645 |
| 2011-11-05 | 8.071 | 8.0674 |
| 2011-11-29 | 8.083 | 8.0802 |
| 2011-12-20 | 8.086 | 8.0811 |
| 2012-01-19 | 8.082 | 8.0876 |
| 2012-03-25 | 8.087 | 8.0905 |
| 2012-05-02 | 8.078 | 8.0789 |
| 2012-05-31 | 8.076 | 8.0725 |
| 2012-06-27 | 8.068 | 8.0664 |
| 2012-08-01 | 8.061 | 8.0563 |
| 2012-08-18 | 8.058 | 8.0499 |
| 2012-09-15 | 8.055 | 8.0477 |
| 2012-10-08 | 8.056 | 8.0587 |
| 2012-12-04 | 8.069 | 8.0697 |