Year	Percent
1991	21.783
1992	23.51
1993	21.431
1994	20.362
1995	20.785
1996	20.339
1997	20.842
1998	16.485
1999	15.077
2000	13.453
2001	12.956
2002	12.664
2003	13.042
2004	13.161
2005	11.533
2006	12.432
2007	11.786
2008	11.483
2009	11.579
2010	11.093
2011	10.636
2012	10.549
2013	10.044
2014	10.5
2015	10.155
2016	10.399
2017	10.114
2018	9.971
2019	9.828
2020	12.618
2021	11.849
2022	10.31