Year	Percent
1991	16.439
1992	16.419
1993	16.552
1994	16.545
1995	16.783
1996	19.51
1997	20.844
1998	17.799
1999	17.856
2000	17.835
2001	17.485
2002	18.462
2003	18.279
2004	18.582
2005	16.534
2006	16.542
2007	16.329
2008	16.599
2009	15.645
2010	15.582
2011	15.505
2012	15.362
2013	14.913
2014	14.662
2015	14.229
2016	14.829
2017	15.203
2018	15.25
2019	15.17
2020	15.07
2021	14.949
2022	14.837