Year	Percent
1991	13.738
1992	13.602
1993	13.933
1994	14.381
1995	14.65
1996	14.133
1997	14.47
1998	14.36
1999	14.724
2000	15.079
2001	15.679
2002	15.884
2003	16.994
2004	17.25
2005	18.225
2006	19.797
2007	21.557
2008	22.709
2009	23.295
2010	23.647
2011	23.169
2012	21.275
2013	21.676
2014	22.117
2015	22.652
2016	22.843
2017	21.882
2018	22.019
2019	22.138
2020	22.237
2021	22.361
2022	22.489