Year	Percent
1991	17.324
1992	17.285
1993	16.916
1994	17.158
1995	17.048
1996	19.099
1997	19.079
1998	18.691
1999	18.307
2000	17.993
2001	18.331
2002	17.938
2003	18.112
2004	18.151
2005	17.772
2006	17.648
2007	17.882
2008	17.521
2009	17.443
2010	18.206
2011	18.022
2012	18.607
2013	19.133
2014	19.73
2015	20.246
2016	22.388
2017	22.899
2018	23.174
2019	23.473
2020	23.713
2021	23.887
2022	24.039