Year	Percent
1991	70.253
1992	70.073
1993	71.246
1994	73.686
1995	74.66
1996	72.425
1997	69.758
1998	71.82
1999	70.258
2000	71.152
2001	72.224
2002	73.45
2003	75.392
2004	75.367
2005	76.602
2006	77.222
2007	78.043
2008	78.398
2009	80.554
2010	80.474
2011	80.317
2012	80.502
2013	80.407
2014	80.079
2015	80.017
2016	79.696
2017	79.427
2018	79.418
2019	79.491
2020	79.68
2021	79.808
2022	79.908