Year	% net
1971	59.36177
1984	83.18713
1985	83.3176
1986	84.19432
1987	84.43713
1988	85.16197
1989	85.4723
1990	91.44414
1992	95.09933
1997	91.55973
1999	85.42788
2000	86.13483
2002	97.12907
2003	96.04654
2004	97.76144
2005	95.32962
2006	95.87482
2007	95.12881
2009	97.70461
2010	96.5537
2011	96.70394
2012	97.93445
2013	98.63946
2014	99.52212
2015	99.69128
2016	99.70946
2017	99.70291