Year	Percent
1991	48.362
1992	48.177
1993	46.305
1994	42.875
1995	42.029
1996	41.358
1997	39.151
1998	41.028
1999	32.668
2000	30.36
2001	33.006
2002	37.688
2003	38.661
2004	39.486
2005	39.156
2006	39.051
2007	35.918
2008	35.889
2009	36.527
2010	37.152
2011	29.348
2012	34.213
2013	33.21
2014	37.917
2015	38.476
2016	40.201
2017	39.843
2018	39.104
2019	38.495
2020	38.104
2021	37.813
2022	37.612