Year	Percent
1991	49.259
1992	50.134
1993	44.057
1994	48.925
1995	46.08
1996	42.999
1997	41.052
1998	40.768
1999	42.038
2000	36.495
2001	37.513
2002	36.674
2003	36.074
2004	36.269
2005	34.881
2006	36.865
2007	36.967
2008	35.746
2009	35.974
2010	35.487
2011	35.436
2012	35.788
2013	34.666
2014	36.971
2015	34.685
2016	35.183
2017	35.574
2018	36.018
2019	36.42
2020	36.556
2021	36.813
2022	36.767