Year	years
1960	41.221
1961	41.59
1962	41.832
1963	41.934
1964	41.67
1965	41.699
1966	41.639
1967	41.663
1968	41.667
1969	41.71
1970	41.755
1971	41.739
1972	41.59
1973	41.707
1974	42.065
1975	42.582
1976	42.635
1977	42.7
1978	42.795
1979	42.744
1980	42.801
1981	40.536
1982	40.703
1983	40.83
1984	38.38
1985	38.657
1986	40.681
1987	40.843
1988	43.844
1989	44.143
1990	44.469
1991	44.66
1992	44.949
1993	45.354
1994	45.606
1995	46.04
1996	46.636
1997	47.408
1998	48.024
1999	48.812
2000	49.491
2001	50.065
2002	50.59
2003	50.87
2004	51.249
2005	51.561
2006	51.961
2007	52.566
2008	53.164
2009	53.788
2010	54.198
2011	54.869
2012	55.639
2013	56.492
2014	57.274
2015	58.151
2016	59.038
2017	59.771
2018	60.526
2019	61.166
2020	61.172
2021	59.325
2022	59.625