7910180
 7920180
 7930180
 7940180
 7950180          Instrument out of operation
 7910280
 7920280
 7930280
 7940280
 7950280          1992 Coefficients in use
 7910380
 7920380
 7930380
 7940380
 7950380          1992 Coefficients in use
 7910480
 7920480
 7930480
 7940480
 7950480          1992 Coefficients in use
 7910580
 7920580
 7930580
 7940580
 7950580          1992 Coefficients in use
 7910680
 7920680
 7930680
 7940680
 7950680          1992 Coefficients in use
 7910780
 7920780
 7930780
 7940780
 7950780          1992 Coefficients in use
 7910880
 7920880
 7930880
 7940880
 7950880          1992 Coefficients in use
 7910980
 7920980
 7930980
 7940980
 7950980          1992 Coefficients in use
 7911080
 7921080
 7931080
 7941080
 7951080          1992 Coefficients in use
 7911180
 7921180
 7931180
 7941180
 7951180          1992 Coefficients in use
 7911280
 7921280
 7931280
 7941280
 7951280          1992 Coefficients in use