1979      4.70
1980      0.79
1981      1.26
1982      2.81
1983      1.73
1984     -1.64
1985      0.05
1986      1.19
1987      2.41
1989      1.87
1990      0.72
1991     -2.58
1992     -0.83
1993      1.60
1994     -0.15
1995     -1.50
1996     -4.26
1997     -2.51
1998     -0.22
1999     -2.51
2000     -2.92
2001     -3.59
2002     -2.65
2003     -2.58
2004     -5.48
2005     -7.97
2006     -8.37
2007     -7.23
2008     -5.41
2009     -5.21
2010     -7.16
2011     -8.71