Year	years
1978	60
1979	60.35
1980	59.84
1981	59.47
1982	60.1
1983	60.5
1984	60.53
1985	60.58
1986	61
1987	61.02
1988	60.68
1989	60.77
1990	61.4
1991	61.7
1992	62.04
1993	62.8
1994	63.34
1995	63.41
1996	63.26
1997	63.12
1998	63.44
1999	63.8
2000	63.46
2001	63.66
2002	64.08
2003	64.65
2004	65.18
2005	65.64
2006	66.08
2007	66.58
2008	66.97
2009	67.56
2010	67.91
2011	68.06
2012	68.4
2013	68.58
2014	68.9
2015	69.44
2016	69.58
2017	69.62
2018	69.87
2019	69.72
2020	69.68
2021	69.97
2022	69.76