# year    value 
 1980     0.42 
 1981      0.3 
 1982    -0.27 
 1983    -0.08 
 1984    -0.67 
 1985     0.77 
 1986     0.51 
 1987     0.66 
 1988     0.28 
 1989     0.33 
 1990     0.62 
 1991        0 
 1992    -0.16 
 1993     0.62 
 1994     0.35 
 1995    -0.33 
 1996     0.19 
 1997      0.6 
 1998     1.17 
 1999      0.6 
 2000     0.27 
 2001     0.31 
 2002     0.08 
 2003     0.74 
 2004     0.78 
 2005     0.59 
 2006      0.7 
 2007    -0.24 
 2008     0.53 
 2009     0.91 
 2010     0.27 
 2011     0.16 
 2012     0.34 
 2013     0.89 
 2014     1.02 
 2015     0.77 
 2016     0.97 
 2017     0.66 
 2018     0.28