Year	%
1989	92.19012
1990	83.00277
1991	37.95196
1992	35.21804
1993	26.8895
1994	26.21312
1995	23.908
1996	28.83257
1997	25.56112
1998	27.24773
1999	25.65854
2000	30.48764
2001	29.03947
2002	28.60209
2003	25.85265
2004	22.13265
2005	15.82848
2006	16.58621
2007	21.34696
2008	21.02516
2009	18.82175
2010	17.63962
2011	18.15436
2012	14.76449
2013	19.21972
2014	17.78452
2015	18.09156
2016	18.89364
2017	18.26614