# year    value 
 1980     0.62 
 1981     0.83 
 1982     0.62 
 1983     0.45 
 1984    -0.98 
 1985    -0.38 
 1986     0.42 
 1987     1.33 
 1988     0.95 
 1989     0.95 
 1990     1.41 
 1991      0.8 
 1992     0.85 
 1993      1.4 
 1994     0.32 
 1995     0.92 
 1996     0.28 
 1997     1.04 
 1998      0.9 
 1999     2.19 
 2000      0.9 
 2001     1.14 
 2002     2.05 
 2003     0.93 
 2004     1.69 
 2005     0.49 
 2006     0.92 
 2007     2.02 
 2008    -0.64 
 2009      2.1 
 2010     1.03 
 2011     0.31 
 2012    -0.68 
 2013     0.64 
 2014     0.72 
 2015      1.7 
 2016     1.92 
 2017     2.34 
 2018     1.05