Year	0-700 m (5-year average)	0-700 m (yearly average)	0-2000 m (5-year average)	0-2000 m (yearly average)
1958	-6.289		-9.303
1959	-4.893		-8.059
1960	-5.784		-8.713
1961	-3.387		-5.479
1962	-2.708		-4.762
1963	-2.604		-4.121
1964	-3.998		-5.697
1965	-4.666		-6.521
1966	-5.374		-7.218
1967	-7.159		-9.122
1968	-7.297	-4.361	-9.059
1969	-6.884	-5.728	-8.991
1970	-5.413	-4.481	-7.62
1971	-4.618	-5.298	-6.838
1972	-3.601	-3.767	-5.627
1973	-3.222	-5.239	-4.77
1974	-3.129	-3.519	-4.087
1975	-2.439	-2.775	-3.354
1976	-1.457	-1.551	-1.398
1977	-0.978	-2.603	-1.445
1978	-0.183	0.032	-1.143
1979	0.975	0.052	0.056
1980	1.58	-0.96	0.068
1981	1.114	1.091	-1.176
1982	0.523	0.122	-1.383
1983	0.486	-2.306	-1.073
1984	0.219	-2.763	-0.974
1985	0.49	-0.459	-0.21
1986	0.648	0.11	0.481
1987	1.066	-1.037	0.718
1988	0.98	-0.893	1.023
1989	0.76	1.088	0.844
1990	0.803	0.903	0.412
1991	1.566	0.177	0.517
1992	2.712	2.646	3.036
1993	3.702	0.572	3.899
1994	3.876	0.684	3.84
1995	3.218	1.51	3.409
1996	3.779	2.264	4.543
1997	4.174	4.544	5.033
1998	4.251	3.245	4.996
1999	4.513	4.304	6.233
2000	4.559	5.943	6.234
2001	5.629	5.857	7.286
2002	6.182	4.117	8.284
2003	7.173	6.789	9.481
2004	8.012	9.952	10.173
2005	9.127	10.24	11.806
2006	9.105	8.412	11.996	10.171
2007	9.314	10.43	12.423	12.638
2008	9.451	9.478	12.664	12.394
2009	10.227	10.052	14.102	13.257
2010	10.443	10.126	14.587	13.431
2011	10.642	10.367	15.229	14.537
2012	11.494	10.869	16.681	15.394
2013		10.941		16.187
2014		12.601		18.65