Year	years
1980	73.9
1981	72.8
1982	74.6
1983	75.3
1984	73.6
1985	76.1
1986	72.6
1987	73
1988	72.8
1989	73.4
1990	74.1
1991	76.5
1992	76.9
1993	75
1994	75.8
1995	79.5
1996	77.4
1997	77
1998	76.1
1999	78.2
2000	77.9
2001	79.4
2002	75.8
2003	76.1
2004	76.4
2005	77.1
2006	75.7
2007	77.6
2008	78.9
2009	78
2010	77.5
2011	78
2012	79.5
2013	76.5
2014	78.3
2015	78.7
2016	80.2
2017	78.5
2018	77.4
2019	78.4
2020	82
2021	75.6
2022	76