Year	years
1960	35.934
1961	36
1962	36.115
1963	36.142
1964	36.159
1965	36.17
1966	36.184
1967	36.221
1968	35.961
1969	35.696
1970	35.449
1971	34.734
1972	35.092
1973	34.999
1974	35.183
1975	35.516
1976	36.085
1977	36.768
1978	37.7
1979	38.482
1980	39.189
1981	39.831
1982	40.069
1983	40.213
1984	40.017
1985	40.001
1986	40.12
1987	40.325
1988	40.677
1989	41.032
1990	41.564
1991	41.823
1992	42.472
1993	43.283
1994	44.117
1995	45.3
1996	46.184
1997	47.008
1998	47.63
1999	48.245
2000	48.881
2001	49.411
2002	50.139
2003	51.173
2004	52.107
2005	53.077
2006	54.026
2007	54.922
2008	55.85
2009	56.742
2010	57.654
2011	58.263
2012	59.013
2013	59.499
2014	60.006
2015	60.069
2016	60.656
2017	61.176
2018	61.611
2019	61.868
2020	60.472
2021	60.407
2022	60.816