Year	Percent
1990	26.18021
1991	21.53455
1992	36.19883
1993	27.9874
1994	26.96572
1995	30.47658
1996	34.09692
1997	34.75054
1998	30.61633
1999	32.22151
2000	37.99703
2001	40.53971
2002	40.82481
2003	41.96958
2004	44.57707
2005	43.01911
2006	43.99242
2007	42.36116
2008	39.16504
2009	32.76604
2010	38.75181
2011	42.64116
2012	42.43758
2013	40.52396
2014	41.63178
2015	41.63536
2016	42.2344
2017	43.5704