Year	Percent
1991	25.026
1992	22.967
1993	23.572
1994	23.63
1995	23.028
1996	22.833
1997	22.312
1998	22.219
1999	22.537
2000	23.097
2001	21.473
2002	22.757
2003	22.812
2004	22.245
2005	22.418
2006	22.575
2007	23.04
2008	23.59
2009	23.971
2010	23.225
2011	23.191
2012	25.499
2013	28.525
2014	29.463
2015	26.756
2016	27.075
2017	26.727
2018	27.306
2019	27.843
2020	28.533
2021	29.274
2022	30.019