Year	Percent
1988	46.22093
1989	48.84058
1990	35.1166
1991	32.24852
1992	12.55023
1993	41.64144
1994	54.61827
1995	71.93538
1996	80.04651
1997	93.89666
1998	58.00947
1999	67.50543
2000	100.91283
2001	78.36214
2002	76.09221
2003	73.48961
2004	69.90898
2005	52.8013
2006	57.15674
2007	68.68651
2008	71.7502
2009	54.50072
2010	58.55551
2011	63.33697
2012	65.55324
2013	61.75012
2014	44.85784
2015	42.29452
2016	42.77039
2017	40.89104