Year	Percent
1991	42.235
1992	43.294
1993	43.519
1994	46.058
1995	46.413
1996	45.824
1997	45.753
1998	46.085
1999	46.648
2000	46.696
2001	46.763
2002	47.883
2003	48.007
2004	46.455
2005	47.698
2006	48.373
2007	49.353
2008	50.352
2009	50.659
2010	51.029
2011	51.376
2012	51.731
2013	51.711
2014	51.625
2015	51.643
2016	51.905
2017	52.186
2018	52.205
2019	52.13
2020	52.002
2021	51.833
2022	51.643