Year	years
1960	36.404
1961	36.556
1962	36.639
1963	36.736
1964	36.744
1965	36.753
1966	36.807
1967	36.83
1968	36.611
1969	36.354
1970	36.062
1971	35.293
1972	35.632
1973	35.704
1974	36.003
1975	36.588
1976	36.976
1977	37.644
1978	38.45
1979	39.202
1980	39.678
1981	40.165
1982	40.301
1983	40.359
1984	40.059
1985	40.031
1986	40.129
1987	40.433
1988	40.79
1989	41.221
1990	41.852
1991	42.218
1992	42.947
1993	43.817
1994	44.714
1995	45.774
1996	46.676
1997	47.505
1998	48.191
1999	48.738
2000	49.322
2001	49.841
2002	50.562
2003	51.434
2004	52.589
2005	53.59
2006	54.596
2007	55.553
2008	56.508
2009	57.396
2010	58.367
2011	58.994
2012	59.65
2013	60.239
2014	60.786
2015	61.083
2016	61.629
2017	62.16
2018	62.454
2019	62.897
2020	61.451
2021	61.576
2022	62.08