Year	Percent
1991	15.186
1992	18.427
1993	19.643
1994	30.845
1995	39.268
1996	31.981
1997	29.36
1998	24.188
1999	22.844
2000	17.986
2001	19.335
2002	20.024
2003	21.487
2004	23.097
2005	22.165
2006	21.4
2007	21.6
2008	29.144
2009	30.821
2010	28.964
2011	29.26
2012	28.171
2013	27.566
2014	27.258
2015	27.161
2016	26.831
2017	26.691
2018	26.434
2019	26.167
2020	25.843
2021	25.494
2022	25.137