Year	Percent
1991	39.174
1992	39.263
1993	40.888
1994	42.857
1995	42.18
1996	42.474
1997	46.071
1998	46.717
1999	46.378
2000	47.076
2001	46.997
2002	48.045
2003	46.559
2004	47.354
2005	48.25
2006	47.25
2007	48.568
2008	49.836
2009	48.4
2010	49.67
2011	52.794
2012	52.387
2013	52.829
2014	52.632
2015	52.316
2016	52.354
2017	51.9
2018	52.166
2019	52.412
2020	52.596
2021	52.572
2022	52.816