Year	Percent
1991	29.193
1992	29.138
1993	28.989
1994	28.811
1995	28.613
1996	28.657
1997	28.633
1998	28.553
1999	28.42
2000	28.257
2001	28.269
2002	28.215
2003	28.107
2004	28.006
2005	30.753
2006	33.732
2007	36.675
2008	39.582
2009	42.441
2010	45.251
2011	48.554
2012	48.54
2013	48.413
2014	48.191
2015	47.877
2016	47.018
2017	46.466
2018	45.965
2019	45.499
2020	45.083
2021	44.71
2022	44.375