Year	% net
1977	76.9349
1978	77.40173
1981	77.92082
1982	77.79511
1983	77.59522
1984	77.17359
1985	77.01762
1986	77.38807
1987	78.68488
1988	80.45377
1989	82.32717
1990	84.04539
1991	84.9129
1992	84.97695
1993	84.43805
1994	83.68513
1995	88.95611
1996	91.01745
2004	94.75558
2005	93.61349
2006	93.16875
2007	93.14766
2008	93.77317
2009	93.91024
2010	93.76425
2011	93.6527
2012	93.57616