1979     -6.33
1980      0.33
1981      9.68
1982    -10.92
1983      2.40
1984      3.20
1985     11.48
1986     -8.85
1988      9.95
1989     -3.72
1990     -4.08
1991     -2.82
1992      0.96
1993     -0.93
1994     -3.90
1995      2.13
1996     -5.25
1997      2.67
1998      2.40
1999      4.28
2000     -2.64
2001     -1.38
2002      4.01
2003      2.40
2004      2.58
2005     -3.45
2006     -5.61
2007     14.00
2008     10.04
2009      2.13
2010      8.87