Year	% net
1971	34.26885
1972	36.38039
1973	38.97356
1977	38.08183
1978	37.84995
1981	42.2307
1982	43.12012
1983	42.50485
1986	50.49967
1987	41.33507
1988	39.87899
1989	40.29103
1990	47.60661
1991	44.41109
2005	40.3517
2006	40.33468
2007	46.82997
2008	54.94259
2009	54.89439
2010	57.04558
2011	55.69895
2012	58.95938