Year	Percent
1991	47.608
1992	48.768
1993	48.336
1994	49.028
1995	48.134
1996	42.122
1997	43.52
1998	42.99
1999	37.396
2000	39.364
2001	38.719
2002	36.726
2003	38.529
2004	37.938
2005	39.326
2006	38.27
2007	37.435
2008	40.817
2009	41.568
2010	38.039
2011	39.408
2012	41.341
2013	42.17
2014	37.058
2015	36.431
2016	38.458
2017	39.828
2018	39.567
2019	39.343
2020	39.252
2021	39.074
2022	38.85