# year    value 
 1980    -0.21 
 1981     0.67 
 1982    -0.23 
 1983    -0.34 
 1984    -0.03 
 1985     0.65 
 1986     0.56 
 1987    -0.14 
 1988     0.88 
 1989     0.22 
 1990      0.5 
 1991     0.08 
 1992     0.04 
 1993    -1.31 
 1994     1.42 
 1995    -0.35 
 1996     1.03 
 1997     0.11 
 1998     0.48 
 1999    -0.12 
 2000     1.03 
 2001        1 
 2002      1.3 
 2003     1.81 
 2004     0.55 
 2005     0.52 
 2006     1.59 
 2007      1.7 
 2008      0.8 
 2009     0.38 
 2010     0.38 
 2011     0.61 
 2012     1.51 
 2013     1.68 
 2014     1.04 
 2015     1.73 
 2016      1.4 
 2017     1.83 
 2018     1.66