1979      1.34
1980      2.68
1981      2.83
1982      3.51
1983      0.59
1984     -1.36
1985     -1.28
1986      0.29
1988      3.13
1989      0.81
1990     -0.68
1991     -1.43
1992      0.66
1993      1.19
1994      1.26
1995     -2.85
1996     -1.66
1997     -0.53
1998     -0.76
1999     -3.60
2000     -4.13
2001     -3.90
2002     -4.05
2003     -4.05
2004     -4.80
2005     -6.67
2006     -8.17
2007     -7.27
2008     -6.22
2009     -6.60
2010    -10.19