Year	Percent
1991	29.854
1992	32.197
1993	34.106
1994	33.129
1995	31.681
1996	32.943
1997	30.967
1998	29.985
1999	28.994
2000	27.808
2001	32.096
2002	35.673
2003	40.179
2004	45.646
2005	50.067
2006	55.4
2007	61.309
2008	66.345
2009	71.201
2010	77.172
2011	78.453
2012	79.279
2013	79.758
2014	80.133
2015	82.014
2016	82.098
2017	82.13
2018	82.277
2019	82.628
2020	82.943
2021	83.245
2022	83.579