Year	years
1960	36.98
1961	37.299
1962	37.707
1963	37.466
1964	37.437
1965	37.351
1966	37.521
1967	37.429
1968	37.386
1969	37.681
1970	38.08
1971	38.559
1972	39.211
1973	39.736
1974	40.327
1975	41.524
1976	42.83
1977	44.07
1978	45.319
1979	46.381
1980	47.318
1981	47.983
1982	48.346
1983	48.396
1984	47.819
1985	47.102
1986	46.444
1987	45.838
1988	45.46
1989	45.465
1990	45.469
1991	45.529
1992	45.619
1993	45.682
1994	45.881
1995	46.035
1996	45.662
1997	45.253
1998	44.925
1999	45.517
2000	46.307
2001	47.645
2002	48.942
2003	50.433
2004	52.143
2005	53.962
2006	55.253
2007	55.922
2008	56.356
2009	57.317
2010	58.41
2011	59.834
2012	61.262
2013	62.633
2014	64.34
2015	64.659
2016	65.671
2017	66.644
2018	66.96
2019	67.968
2020	67.597
2021	66.469
2022	66.326