Year	years
1960	50.877
1961	51.206
1962	51.45
1963	51.656
1964	51.889
1965	52.123
1966	52.223
1967	52.35
1968	52.557
1969	52.811
1970	53.146
1971	53.449
1972	53.701
1973	54.119
1974	54.443
1975	54.77
1976	55.215
1977	55.623
1978	56.055
1979	56.457
1980	56.891
1981	57.413
1982	58.006
1983	58.516
1984	59.023
1985	59.451
1986	59.796
1987	60.011
1988	60.115
1989	60.143
1990	59.93
1991	59.506
1992	59.534
1993	59.103
1994	58.777
1995	58.441
1996	57.762
1997	57.276
1998	56.624
1999	55.991
2000	55.397
2001	54.565
2002	53.191
2003	51.97
2004	51.891
2005	52.064
2006	52.209
2007	52.691
2008	53.488
2009	54.728
2010	56.067
2011	57.731
2012	58.775
2013	59.352
2014	60.062
2015	60.709
2016	61.307
2017	61.954
2018	62.203
2019	62.834
2020	62.178
2021	59.458
2022	58.597