Year	Percent
1991	41.13628
1992	41.69863
1993	41.58914
1994	42.41621
1995	43.53312
1996	43.54975
1997	43.16266
1998	42.56866
1999	42.59591
2000	41.25953
2001	40.07051
2002	40.15832
2003	39.85085
2004	39.50343
2005	39.27832
2006	39.58672
2007	38.55287
2008	39.59296
2009	38.18437
2010	38.3044
2011	37.89404
2012	37.65
2013	37.10001
2014	36.75369
2015	36.36001
2016	36.34001
2017	36.34999
2018	36.26001
2019	35.98199