Year	Percent
1991	49.171
1992	46.574
1993	46.828
1994	45.686
1995	46.25
1996	46.333
1997	45.781
1998	45.292
1999	44.825
2000	45.059
2001	44.804
2002	44.499
2003	44.295
2004	44.199
2005	43.894
2006	43.335
2007	43.164
2008	43.167
2009	43.376
2010	42.972
2011	42.001
2012	42.12
2013	42.05
2014	42.644
2015	41.858
2016	41.158
2017	41.021
2018	40.884
2019	40.747
2020	40.615
2021	40.486
2022	40.361