# year    value 
 1980      0.3 
 1981     0.26 
 1982      0.3 
 1983     0.63 
 1984     0.17 
 1985     0.11 
 1986     0.26 
 1987     0.92 
 1988     0.38 
 1989     0.34 
 1990     0.39 
 1991     0.43 
 1992     0.33 
 1993     0.55 
 1994     0.24 
 1995     0.68 
 1996     0.47 
 1997     0.67 
 1998     1.07 
 1999     0.42 
 2000     0.49 
 2001     0.63 
 2002     0.88 
 2003     0.67 
 2004     0.65 
 2005     0.81 
 2006     0.78 
 2007     0.64 
 2008     0.51 
 2009     1.09 
 2010      0.9 
 2011     0.91 
 2012      0.8 
 2013     0.65 
 2014     1.05 
 2015     1.19 
 2016     1.14 
 2017      1.1 
 2018     0.91