1979      6.26
1980      4.83
1981      2.48
1982      7.70
1983      9.00
1984      2.61
1985     -2.73
1986      4.44
1987      0.27
1988      3.00
1989      3.27
1990    -11.08
1991     -3.51
1992      2.48
1993     -4.95
1994     -0.78
1995    -12.90
1996      6.53
1997     -4.82
1998     -2.34
1999     -3.78
2000     -5.99
2001     -2.60
2002    -14.86
2003    -10.69
2004    -10.95
2005    -17.86
2006    -14.99
2007    -30.11
2008    -21.12
2009    -18.12
2010    -21.64
2011    -28.03
2012    -38.46