Year	Percent
1996	14.25078
1997	14.70741
1998	14.78943
1999	15.50904
2000	16.12958
2001	16.11536
2009	17.97325
2010	18.66228
2011	18.97298
2012	18.95103
2014	19.6239
2015	20.62643
2016	20.54059