Year	Percent
1991	31.398
1992	31.384
1993	32.355
1994	33.135
1995	33.766
1996	31.715
1997	34.896
1998	37.081
1999	36.989
2000	36.032
2001	38.738
2002	38.953
2003	38.288
2004	37.601
2005	40.532
2006	40.862
2007	42.624
2008	43.342
2009	41.9
2010	39.261
2011	40.239
2012	40.428
2013	41.434
2014	43.618
2015	43.047
2016	39.871
2017	40.666
2018	40.977
2019	41.263
2020	41.503
2021	41.722
2022	41.904