Year	% net
1971	11.74967
1972	13.00527
1974	16.89654
1975	18.61373
1976	19.62819
1977	20.7334
1998	32.79017
1999	29.99388
2000	28.2903
2001	31.64308
2002	30.77497
2003	30.10294
2004	35.7166
2005	33.0117
2006	27.55351
2007	36.56994
2009	32.85487
2010	33.32982
2011	37.23711
2012	36.95593
2013	35.02331
2014	35.52315
2015	36.35775