# year    value 
 1980     0.25 
 1981     0.33 
 1982     0.04 
 1983     0.55 
 1984     0.02 
 1985     0.13 
 1986     0.03 
 1987     0.32 
 1988     0.35 
 1989     0.28 
 1990      0.5 
 1991     0.46 
 1992    -0.16 
 1993    -0.11 
 1994     0.56 
 1995     0.67 
 1996     0.29 
 1997     0.72 
 1998     0.69 
 1999     0.64 
 2000      0.4 
 2001     0.81 
 2002     0.71 
 2003      0.9 
 2004     0.95 
 2005     1.26 
 2006     0.96 
 2007     0.96 
 2008     0.95 
 2009     0.98 
 2010     1.14 
 2011     1.01 
 2012     1.08 
 2013     1.05 
 2014      0.9 
 2015     1.32 
 2016     1.14 
 2017     1.17 
 2018     1.05