Year	Percent
1991	29.444
1992	31.406
1993	24.259
1994	31.738
1995	28.613
1996	25.886
1997	23.855
1998	24.011
1999	25.61
2000	17.954
2001	19.23
2002	18.63
2003	18.128
2004	17.983
2005	16.506
2006	18.207
2007	18.029
2008	16.628
2009	15.454
2010	15.387
2011	15.238
2012	15.106
2013	14.184
2014	14.554
2015	13.874
2016	13.975
2017	14.316
2018	14.542
2019	14.716
2020	14.675
2021	14.764
2022	14.549