Year	years
1960	38.553
1961	38.874
1962	38.952
1963	39.331
1964	39.633
1965	39.794
1966	39.825
1967	39.309
1968	40.139
1969	40.263
1970	40.658
1971	41.285
1972	42.063
1973	42.693
1974	43.478
1975	44.407
1976	45.563
1977	46.535
1978	47.104
1979	47.265
1980	47.498
1981	47.504
1982	47.62
1983	47.735
1984	47.659
1985	47.551
1986	47.148
1987	47.344
1988	47.477
1989	47.643
1990	47.554
1991	47.27
1992	47.28
1993	47.438
1994	47.026
1995	47.056
1996	47.171
1997	47.273
1998	47.226
1999	47.826
2000	48.328
2001	48.689
2002	49.024
2003	49.54
2004	49.78
2005	50.255
2006	50.575
2007	50.819
2008	50.773
2009	51.242
2010	51.404
2011	51.791
2012	51.896
2013	52.115
2014	52.196
2015	52.202
2016	52.229
2017	52.589
2018	52.77
2019	53.165
2020	53.323
2021	53.07
2022	53.968