Year	years
1960	33.961
1961	34.412
1962	34.875
1963	35.344
1964	35.87
1965	36.363
1966	36.868
1967	37.434
1968	37.846
1969	38.249
1970	38.793
1971	39.269
1972	39.767
1973	40.217
1974	40.691
1975	41.173
1976	41.631
1977	42.06
1978	42.46
1979	42.873
1980	43.13
1981	43.364
1982	43.571
1983	43.8
1984	43.916
1985	43.888
1986	43.792
1987	44.047
1988	44.047
1989	44.021
1990	44.057
1991	43.506
1992	43.621
1993	43.594
1994	42.925
1995	42.716
1996	43.68
1997	43.715
1998	42.789
1999	42.071
2000	45.05
2001	45.661
2002	46.359
2003	46.963
2004	47.577
2005	48.237
2006	49.323
2007	50.365
2008	51.526
2009	52.626
2010	53.693
2011	54.62
2012	55.451
2013	56.313
2014	56.393
2015	57.189
2016	58.404
2017	58.652
2018	59.796
2019	60.255
2020	59.763
2021	60.062
2022	60.411