Year	Percent
1991	50.201
1992	50.905
1993	51.245
1994	50.496
1995	50.453
1996	49.97
1997	49.73
1998	48.978
1999	48.639
2000	48.255
2001	48.165
2002	48.318
2003	47.889
2004	47.89
2005	47.889
2006	41.652
2007	41.312
2008	39.626
2009	39.441
2010	39.235
2011	39.014
2012	38.866
2013	38.678
2014	38.206
2015	38.171
2016	38.066
2017	37.895
2018	37.849
2019	37.802
2020	37.75
2021	37.698
2022	37.652