Year	Percent
1991	26.953
1992	27.382
1993	29.263
1994	29.592
1995	29.633
1996	29.893
1997	30.61
1998	30.601
1999	32.902
2000	32.182
2001	32.281
2002	32.483
2003	32.551
2004	32.985
2005	33.177
2006	33.98
2007	33.813
2008	33.029
2009	31.58
2010	30.553
2011	30.27
2012	30.307
2013	29.957
2014	29.668
2015	29.812
2016	29.877
2017	30.103
2018	30.167
2019	30.153
2020	30.094
2021	30.035
2022	29.965