Year	Percent
1991	43.192
1992	39.306
1993	35.078
1994	35.074
1995	35.201
1996	35.688
1997	37.88
1998	39.009
1999	37.213
2000	37.345
2001	37.299
2002	40.4
2003	41.73
2004	42.987
2005	42.322
2006	41.878
2007	41.679
2008	41.817
2009	41.678
2010	48.29
2011	42.942
2012	44.118
2013	45.29
2014	48.114
2015	47.899
2016	48.733
2017	48.379
2018	48.642
2019	49.089
2020	49.477
2021	49.879
2022	50.306