Year	Percent
1991	37.443
1992	39.86
1993	42.229
1994	44.284
1995	43.784
1996	43.425
1997	43.01
1998	42.479
1999	42.028
2000	41.672
2001	41.572
2002	41.593
2003	41.664
2004	42.608
2005	43.438
2006	44.89
2007	44.982
2008	44.878
2009	44.789
2010	44.709
2011	44.673
2012	44.661
2013	44.685
2014	44.6
2015	44.467
2016	44.443
2017	44.429
2018	44.401
2019	44.342
2020	44.247
2021	44.189
2022	44.097