Year	Percent
1991	67.026
1992	67.846
1993	69.63
1994	71.437
1995	74.83
1996	73.925
1997	73.255
1998	74.418
1999	74.824
2000	78.932
2001	78.766
2002	79.194
2003	79.302
2004	80.274
2005	82.614
2006	82.474
2007	82.033
2008	82.605
2009	77.382
2010	78.464
2011	85.34
2012	85.204
2013	85.139
2014	87.407
2015	87.572
2016	88.252
2017	88.226
2018	88.347
2019	88.49
2020	88.628
2021	88.775
2022	88.93
