Year	Percent
1991	49.042
1992	47.828
1993	47.091
1994	45.606
1995	44.307
1996	39.913
1997	38.015
1998	36.023
1999	34.31
2000	32.958
2001	33.769
2002	34.131
2003	34.127
2004	34.011
2005	35.384
2006	33.348
2007	25.989
2008	23.213
2009	20.401
2010	17.761
2011	19.923
2012	22.147
2013	22.344
2014	23.328
2015	24.257
2016	23.95
2017	23.884
2018	23.497
2019	23.121
2020	22.719
2021	22.348
2022	22.044