Year	Percent
1991	28.998
1992	19.231
1993	25.329
1994	28.313
1995	22.579
1996	24.089
1997	26.896
1998	32.981
1999	33.176
2000	33.485
2001	32.559
2002	29.907
2003	28.303
2004	25.86
2005	23.84
2006	21.435
2007	20.686
2008	17.016
2009	15.929
2010	16.366
2011	15.525
2012	14.012
2013	13.296
2014	12.486
2015	11.758
2016	11.195
2017	10.939
2018	10.529
2019	10.143
2020	9.711
2021	9.29
2022	8.869