Year	Percent
1990	67.66
1991	68.2
1992	69.18
1993	69.5
1994	70.88
1995	71.55
1996	71.07
1997	70.76
1998	71.07
1999	71.29
2000	71.13
2001	70.55
2002	71.76
2003	71.84
2004	69.67
2005	71.3
2006	71.93
2007	73.05
2008	73.6
2009	74.17
2010	74.42
2011	74.77
2012	75.32
2013	75.64
2014	75.42
2015	75.51
2016	76.18
2017	76.33
2018	76.63
2019	76.86