Year	Percent
1999	16.29397
2000	28.70338
2001	29.24668
2002	18.99829
2003	21.55708
2004	21.67386
2005	22.40371
2006	29.31213
2007	23.21255
2008	26.97887
2009	17.09994
2010	16.85608
2011	17.29032
2012	16.66116
2013	15.52444
2014	15.57108
2015	12.45712
2016	10.32323