Year	years
1960	28.662
1961	28.84
1962	29.119
1963	28.826
1964	33.149
1965	29.288
1966	26.084
1967	26.406
1968	26.708
1969	26.086
1970	26.399
1971	31.582
1972	31.907
1973	36.479
1974	36.514
1975	36.746
1976	36.84
1977	37.325
1978	37.649
1979	37.919
1980	38.417
1981	38.783
1982	39.113
1983	35.491
1984	32.673
1985	33.154
1986	33.632
1987	21.912
1988	12.407
1989	29.68
1990	29.935
1991	30.148
1992	22.724
1993	22.704
1994	44.384
1995	30.948
1996	31.297
1997	32.242
1998	18.385
1999	43.223
2000	46.028
2001	46.881
2002	47.492
2003	50.253
2004	50.917
2005	51.545
2006	52.016
2007	52.856
2008	53.538
2009	53.891
2010	54.812
2011	54.94
2012	55.865
2013	55.751
2014	54.973
2015	55.566
2016	55.544
2017	55.309
2018	55.95
2019	55.912
2020	55.48
2021	54.975
2022	55.567