# year    value 
 1980 0.2547779 
 1981  0.41463 
 1982 0.1091538 
 1983 -0.1716793 
 1984 0.004356069 
 1985 0.1948849 
 1986 0.1214736 
 1987 0.450397 
 1988 0.5480353 
 1989 0.4883067 
 1990 0.8949828 
 1991 0.747629 
 1992 0.2230382 
 1993 0.4060894 
 1994 0.4700133 
 1995 0.7670324 
 1996 0.917459 
 1997 0.9128062 
 1998 1.161415 
 1999 1.225852 
 2000 1.297216 
 2001 1.291234 
 2002 1.589615 
 2003 1.482483 
 2004  1.57085 
 2005 1.583572