#Digitized by W Eschenbach from Yao et al 2006 Email
 1967, -10.34  
 1968, -9.73  
 1969, -9.13  
 1970, -10.68  
 1971, -10.45  
 1972, -9.96  
 1973, -9.82  
 1974, -9.94  
 1975, -10.33  
 1976, -11.17  
 1977, -11.58  
 1978, -8.49  
 1979, -10.21  
 1980, -10.02  
 1981, -9.23  
 1982, -9.38  
 1983, -9.17  
 1984, -13.31  
 1985, -7.93