Year	Percent
1991	4.781
1992	5.22
1993	5.395
1994	5.625
1995	5.935
1996	7.129
1997	11.721
1998	12.692
1999	14.829
2000	16.301
2001	21.675
2002	24.091
2003	25.681
2004	30.446
2005	32.879
2006	33.544
2007	35.277
2008	37.823
2009	36.348
2010	34.183
2011	34.397
2012	35.083
2013	34.346
2014	33.398
2015	31.371
2016	29.848
2017	28.928
2018	28.037
2019	27.741
2020	27.122
2021	27.093
2022	27.018