Year	Percent
1991	21.01292
1992	20.79654
1993	20.60942
1994	20.43344
1995	20.21945
1996	20.01053
1997	19.77481
1998	19.43369
1999	19.1283
2000	18.77798
2001	18.39904
2002	18.04949
2003	17.68874
2004	17.26563
2005	16.85601
2006	16.41571
2007	15.87018
2008	15.34561
2009	14.82632
2010	14.44726
2011	14.09353
2012	13.75773
2013	13.41291
2014	13.11172
2015	12.80768
2016	12.44601
2017	12.08108
2018	11.68796
2019	11.31688