Year	Percent
1999	23.89234
2000	20.15528
2001	21.22535
2002	23.19713
2004	16.84509
2006	16.06278
2007	16.90337
2008	17.72471
2009	20.93383
2010	22.96996
2011	23.05647
2012	24.10924
2013	24.28808
2014	23.71264
2015	24.88973
2016	23.71722