Year	Percent
1991	34.294
1992	32.722
1993	30.734
1994	30.032
1995	29.321
1996	29.386
1997	29.422
1998	29.83
1999	31.108
2000	33.003
2001	34.956
2002	36.049
2003	36.788
2004	37.515
2005	37.947
2006	40.105
2007	42.18
2008	43.487
2009	43.28
2010	43.132
2011	42.747
2012	42.406
2013	44.254
2014	42.494
2015	44.341
2016	45.602
2017	45.534
2018	45.965
2019	46.331
2020	46.754
2021	47.179
2022	47.618