Year	years
1960	37.377
1961	37.73
1962	38.111
1963	38.429
1964	38.914
1965	39.27
1966	39.666
1967	40.055
1968	40.44
1969	40.88
1970	41.184
1971	41.495
1972	42.05
1973	42.406
1974	42.858
1975	43.312
1976	44.027
1977	44.502
1978	44.974
1979	45.169
1980	45.585
1981	45.952
1982	46.351
1983	46.643
1984	46.874
1985	47.602
1986	48.29
1987	48.812
1988	49.643
1989	50.006
1990	50.592
1991	50.894
1992	51.431
1993	52.123
1994	52.711
1995	53.393
1996	53.962
1997	54.304
1998	54.357
1999	54.654
2000	54.684
2001	54.924
2002	55.158
2003	55.263
2004	55.552
2005	55.703
2006	56.033
2007	56.379
2008	56.462
2009	56.568
2010	57.014
2011	57.163
2012	57.627
2013	57.696
2014	57.962
2015	58.058
2016	58.332
2017	58.505
2018	58.916
2019	59.05
2020	58.693
2021	58.221
2022	58.265