U.S. base oil production dropped 5.3 percent compared to the first quarter of last year. Paraffinic production was down 6.8 percent, while naphthenic production fell 0.9 percent, according to statistics reprinted from the U.S. Department of Energy. Wax production showed the lone improvement with a 6 percent increase.

The decrease in finished lubricant sales dropped first-quarter volumes to 94 percent of the quarterly average for 1997, the base year for the index. Volumes for the second and third quarters are normally higher than the first and fourth quarters.

The automotive index fell to 98.8 percent, while the industrial index dropped to 88.6 percent. The index for grease has now fallen to 59.8 percent of the average quarterly level from 1997.

The quarterly index is meant to signal general sales trends of lubricants in the United States, not as a measurement of the markets total volume. The association noted that suppliers participating in the quarterly reports account for approximately 75 percent of the volume included in its annual lubricating oil sales reports. The association also acknowledged that quarterly indices reliability even as a trend indicator may have suffered in recent years due to mergers and other changes in the survey population.