Year	Percent
1991	53.024
1992	52.606
1993	51.482
1994	50.33
1995	49.164
1996	48.217
1997	47.266
1998	46.411
1999	44.113
2000	44.808
2001	45.862
2002	46.921
2003	47.985
2004	49.054
2005	50.134
2006	51.227
2007	50.998
2008	50.759
2009	50.509
2010	50.319
2011	51.391
2012	52.468
2013	54.177
2014	53.699
2015	53.218
2016	52.794
2017	52.88
2018	52.971
2019	53.035
2020	53.081
2021	53.12
2022	53.149