Year	years
1960	36.811
1961	37.098
1962	37.382
1963	37.558
1964	37.793
1965	37.565
1966	37.139
1967	37.46
1968	37.952
1969	38.272
1970	38.559
1971	38.216
1972	39.267
1973	40.064
1974	40.168
1975	40.303
1976	40.035
1977	40.248
1978	40.541
1979	40.811
1980	41.041
1981	41.105
1982	41.481
1983	41.728
1984	42.135
1985	43.018
1986	42.954
1987	38.766
1988	44.081
1989	44.033
1990	41.782
1991	44.437
1992	44.698
1993	45.181
1994	45.365
1995	45.688
1996	45.97
1997	46.231
1998	46.203
1999	46.399
2000	46.325
2001	46.888
2002	47.012
2003	47.307
2004	47.158
2005	47.33
2006	47.083
2007	47.521
2008	47.788
2009	48.045
2010	48.388
2011	48.76
2012	49.255
2013	49.431
2014	49.808
2015	50.09
2016	50.867
2017	50.898
2018	51.372
2019	51.664
2020	51.218
2021	50.845
2022	51.3