Year	Percent
1991	34.034
1992	33.218
1993	33.064
1994	34.394
1995	35.61
1996	37.026
1997	37.659
1998	38.013
1999	38.92
2000	39.405
2001	40.264
2002	40.754
2003	42.428
2004	45.656
2005	47.611
2006	48.94
2007	48.25
2008	49.788
2009	48.418
2010	48.835
2011	49.771
2012	49.604
2013	50.492
2014	50.945
2015	49.535
2016	48.208
2017	47.907
2018	47.699
2019	47.56
2020	47.387
2021	47.214
2022	47.018