Year	Percent
1991	41.75
1992	41.73
1993	42.282
1994	44.425
1995	45.189
1996	47.085
1997	46.209
1998	47.788
1999	46.118
2000	47.664
2001	48.707
2002	49.646
2003	50.453
2004	50.822
2005	50.558
2006	50.698
2007	51.28
2008	51.825
2009	51.753
2010	51.743
2011	51.768
2012	52.556
2013	52.231
2014	51.224
2015	50.842
2016	50.896
2017	50.631
2018	50.654
2019	50.684
2020	50.784
2021	50.847
2022	50.924