Year	Percent
1991	43.724
1992	47.455
1993	43.93
1994	46.85
1995	42.259
1996	40.765
1997	45.051
1998	49.712
1999	48.655
2000	48.103
2001	47.513
2002	41.642
2003	40.59
2004	39.029
2005	37.754
2006	38.162
2007	37.424
2008	38.635
2009	36.981
2010	38.193
2011	37.627
2012	33.84
2013	33.306
2014	31.831
2015	31.413
2016	30.818
2017	29.72
2018	28.942
2019	28.478
2020	27.891
2021	27.343
2022	26.9