Year	Percent
1991	51.053
1992	48.292
1993	49.265
1994	49.183
1995	48.832
1996	51.839
1997	53.678
1998	50.709
1999	55.059
2000	56.123
2001	53.367
2002	29.207
2003	29.258
2004	30.01
2005	30.71
2006	30.369
2007	31.129
2008	28.073
2009	21.689
2010	24.155
2011	16.986
2012	17.415
2013	17.66
2014	16.318
2015	16.36
2016	16.153
2017	16.071
2018	16.027
2019	15.982
2020	15.923
2021	15.872
2022	15.82