Year	Percent
1991	38.752
1992	39.419
1993	39.169
1994	43.206
1995	39.943
1996	38.44
1997	31.172
1998	31.007
1999	31.004
2000	31.198
2001	37.993
2002	38.052
2003	37.99
2004	37.206
2005	34.23
2006	33.258
2007	32.223
2008	31.095
2009	30.748
2010	29.426
2011	29.127
2012	29.998
2013	30.261
2014	30.147
2015	31.443
2016	31.885
2017	31.899
2018	31.849
2019	31.76
2020	31.669
2021	31.592
2022	31.52