Year	Percent
1999	15.98
2000	12.23
2001	13.12
2002	13.88
2003	12.57
2004	14.17
2005	15.85
2007	14.65
2008	19.43
2009	22.45
2010	21.23
2011	20.69
2012	20.86
2013	20.77
2014	18.94
2015	17.97
2016	18.57
2017	15.21
2018	13.58
2019	12.67
2020	18.85