Year	Percent
1991	30.453
1992	31.051
1993	32.195
1994	33.563
1995	35.127
1996	36.613
1997	38.171
1998	41.323
1999	43.919
2000	45.594
2001	46.316
2002	47.318
2003	47.653
2004	48.112
2005	50.288
2006	50.981
2007	52.104
2008	51.715
2009	49.393
2010	48.068
2011	47.293
2012	46.954
2013	47.435
2014	47.772
2015	48.59
2016	49.77
2017	50.155
2018	50.07
2019	49.784
2020	49.614
2021	49.497
2022	49.394