Year	years
1960	33.422
1961	33.373
1962	33.624
1963	33.776
1964	33.944
1965	34.088
1966	34.202
1967	34.352
1968	34.669
1969	34.942
1970	35.362
1971	35.899
1972	36.576
1973	37.33
1974	38.194
1975	38.897
1976	39.607
1977	40.391
1978	41.271
1979	42.176
1980	42.906
1981	43.461
1982	43.691
1983	43.738
1984	43.388
1985	42.84
1986	42.291
1987	41.83
1988	41.382
1989	41.29
1990	41.251
1991	41.177
1992	41.284
1993	41.182
1994	41.33
1995	41.343
1996	41.307
1997	41.098
1998	40.865
1999	41.696
2000	42.781
2001	44.186
2002	45.532
2003	47.161
2004	48.769
2005	50.139
2006	51.232
2007	51.967
2008	52.82
2009	53.551
2010	54.331
2011	55.084
2012	56.116
2013	56.868
2014	57.577
2015	58.187
2016	58.86
2017	59.449
2018	59.724
2019	60.402
2020	60.014
2021	59.493
2022	59.58