Year	January	March	February	September	March trend	September trend
1979		16.846		8.002
1980		16.512		8.75
1981		16.14		8.173
1982		16.531		8.251
1983		16.525		8.455
1984		15.981		7.88
1985		16.315		7.799
1986		16.298		8.148
1987		16.174		8.146
1988		16.348		8.155
1989		15.856		7.749
1990		16.336		6.943
1991		15.804		7.241
1992		16.038		8.241
1993		16.224		7.323
1994		15.969		8.023
1995		15.655		6.817
1996		15.531		8.417
1997		15.897		7.416
1998		16.023		7.497
1999		15.71		7.184
2000		15.638		7.281
2001		15.848		7.593
2002		15.753		6.595
2003		15.841		6.894
2004		15.31		6.636
2005		15.036		6.187
2006		14.767		6.563
2007		14.913		4.962
2008		15.436		5.39
2009		15.258		5.893
2010		15.425		5.605
2011		14.876		5.173
2012		15.471		4.146
2013		15.432		6.163
2014		15.333		6.303
2015		14.899		5.777
2016		14.987