1979     12.86
1980     -6.71
1981    -11.26
1982      7.72
1983     -2.36
1984      1.79
1985    -11.45
1986     10.29
1987      2.18
1989     -3.35
1990      1.20
1991      7.52
1992     -4.34
1993     -9.28
1994      2.58
1995     15.23
1996     21.95
1997    -15.60
1998    -12.05
1999     -2.16
2000     -4.73
2001      5.94
2002     -7.11
2003     22.54
2004     14.24
2005     -2.56
2006    -16.00
2007     -3.75
2008     35.98
2009     17.60
2010     -2.56
2011     -7.50
2012     13.84