# year    value 
 1980     0.78 
 1981     0.79 
 1982     0.43 
 1983     1.23 
 1984      0.2 
 1985     0.49 
 1986     0.44 
 1987     0.54 
 1988     0.26 
 1989    -0.05 
 1990     0.18 
 1991     0.89 
 1992     1.12 
 1993     0.61 
 1994     0.77 
 1995     0.52 
 1996      0.5 
 1997        1 
 1998     1.04 
 1999     0.01 
 2000     0.17 
 2001     0.31 
 2002     0.87 
 2003     0.61 
 2004     0.32 
 2005     0.43 
 2006     0.41 
 2007     0.19 
 2008     0.14 
 2009     1.17 
 2010     0.83 
 2011     0.39 
 2012     0.88 
 2013     0.59 
 2014     0.54 
 2015     1.49 
 2016     0.74 
 2017     0.91 
 2018     1.04