Year	Percent
1991	47.681
1992	47.287
1993	47.133
1994	46.85
1995	46.632
1996	46.463
1997	46.368
1998	46.012
1999	45.479
2000	44.984
2001	44.256
2002	43.328
2003	42.778
2004	42.431
2005	41.954
2006	40.448
2007	39.392
2008	38.591
2009	37.988
2010	37.302
2011	36.177
2012	34.982
2013	33.711
2014	30.843
2015	29.668
2016	28.251
2017	27.928
2018	27.875
2019	28.241
2020	28.919
2021	29.507
2022	29.847