Year	Percent
1991	22.13
1992	21.845
1993	21.128
1994	20.395
1995	19.489
1996	19.401
1997	15.405
1998	15.867
1999	13.613
2000	14.226
2001	17.621
2002	17.066
2003	16.301
2004	14.562
2005	12.275
2006	10.639
2007	10.619
2008	10.158
2009	10.324
2010	4.706
2011	4.759
2012	4.84
2013	4.729
2014	4.68
2015	4.814
2016	4.727
2017	4.739
2018	4.754
2019	4.764
2020	4.785
2021	4.806
2022	4.822