Year	Percent
1991	18.81
1992	21.17
1993	23.993
1994	27.224
1995	31.095
1996	35.916
1997	41.51
1998	48.442
1999	49.723
2000	51.048
2001	51.531
2002	51.728
2003	47.79
2004	50.495
2005	47.29
2006	43.326
2007	44.105
2008	45.104
2009	46.93
2010	48.079
2011	49.123
2012	43.374
2013	41.928
2014	42.059
2015	42.547
2016	39.526
2017	39.517
2018	39.043
2019	38.565
2020	38.067
2021	37.682
2022	37.202