Year	% net
1971	14.57018
1973	20.21817
1974	21.58367
1975	22.94764
1976	25.1567
1977	27.31791
1978	28.7257
1979	30.62815
1980	31.27506
1981	30.00673
1995	35.25775
1996	35.4178
1997	35.76629
1998	36.61892
1999	36.97529
2000	37.84165
2001	39.04989
2002	39.29134
2003	55.84693
2004	59.39974
2005	62.79255
2006	62.90708
2007	65.10803
2008	65.98292
2009	66.35944
2010	66.96466
2011	68.75115
2012	72.18354
2013	48.07895