Year	years
1960	39.971
1961	40.196
1962	40.312
1963	40.618
1964	40.908
1965	40.716
1966	41.271
1967	41.605
1968	41.947
1969	42.354
1970	42.749
1971	42.256
1972	43.638
1973	43.536
1974	43.429
1975	43.464
1976	44.113
1977	44.334
1978	44.529
1979	44.873
1980	45.143
1981	45.596
1982	46.059
1983	46.755
1984	47.001
1985	47.121
1986	47.538
1987	47.422
1988	47.494
1989	47.738
1990	47.793
1991	47.438
1992	47.5
1993	47.438
1994	47.514
1995	47.713
1996	48.041
1997	48.187
1998	48.234
1999	48.335
2000	48.557
2001	48.802
2002	48.875
2003	49.102
2004	49.313
2005	49.304
2006	49.515
2007	50.005
2008	50.281
2009	50.361
2010	50.798
2011	51.279
2012	51.849
2013	52.16
2014	52.63
2015	53.132
2016	53.317
2017	53.752
2018	54.317
2019	54.908
2020	54.396
2021	54.283
2022	54.769