Year	Percent
1991	12.515
1992	12.316
1993	12.283
1994	12.161
1995	12.348
1996	12.454
1997	12.648
1998	15.154
1999	15.238
2000	15.289
2001	15.38
2002	15.585
2003	15.603
2004	15.816
2005	15.989
2006	16.145
2007	16.352
2008	16.49
2009	16.733
2010	17.641
2011	16.343
2012	13.012
2013	14.715
2014	14.959
2015	14.121
2016	13.297
2017	12.623
2018	13.078
2019	13.2
2020	13.274
2021	13.678
2022	14.041