1979     -1.29
1980      3.47
1981      1.50
1982     -1.46
1983     -0.86
1984     -2.83
1985      0.84
1986     -3.59
1987     -1.40
1988      1.83
1989     -1.29
1990     -0.47
1991     -0.36
1992     -0.25
1993      0.62
1994     -0.03
1995      0.18
1996     -0.53
1997     -0.69
1998      3.03
1999      2.54
2000      1.06
2001     -1.02
2002     -0.53
2003      0.57
2004      1.66
2005      2.37
2006      3.96
2007      2.26
2008     -1.02
2009      1.83
2010      3.09
2011      1.17
2012      3.36