Year	%
1990	75.90635
1991	77.55324
1992	79.59318
1993	79.59024
1994	81.27976
1995	83.99685
1996	84.72445
1997	84.95179
1998	85.06479
1999	86.10268
2000	86.69004
2001	88.31093
2002	89.57508
2003	88.61384
2004	88.57707
2005	89.85817
2006	91.07396
2007	91.56037
2008	91.9153
2009	92.2364
2010	92.43675
2011	92.26774
2012	91.23112
2014	91.39441
2016	91.74907
2017	92.42873