WASHINGTON -- US foreign military sales dropped by around $10 billion in 2016, but the Pentagon's top weapon sales official isn't concerned that interest is waning globally.

Vice Adm. Joseph Rixey, director of the Defense Security Cooperation Agency, said during the AUSA conference that the unofficial tally of FMS deals is at "about the mid-30s" in terms of billions of dollars. Those totals are not finalized for the year but are unlikely to shift much.

At least year's AUSA conference, Rixey announced 2015 had brought in a record $46.6 billion, but predicted that the 2016 total would drop due to lower oil prices and cuts to global defense budgets. While the drop happened as predicted, Rixey said he learned an important lesson about assuming a root cause.

"I have spent the entire year trying to correlate something to pricing, and in fact we have found you can’t really correlate that. My answer to you is we don’t have an economic indicator out there," Rixey told reporters after his speech. "It could also be currency difference. There are so many factors that it’s not what I thought it was. I thought we could directly correlate it."

"Now, I’m sure oil price is having an impact on that particular number, but I didn’t find the correlation I was looking for," he added.

The drop in dollar value is also partly misleading, Rixey noted, because a number of high-end sales – most notably a trio of fighter jet sales to Kuwait, Qatar and Bahrain – have been delayed. The package reportedly includes 72 Boeing F-15E Strike Eagles for Qatar and up to 40 Boeing F/A-18 E/F Super Hornets for Kuwait. Bahrain’s package includes Lockheed Martin F-16 fighters.

"What would have happened if they had gone this year? We would have had record sales again," Rixey said. "So we’ve decided maybe we should look at this like a rolling three-year number" in order to have a truer sense of trends.

But Rixey also downplayed the overall figure, noting that the US does not set a sales target each year.

"We don’t look at sales like a benchmark we’re trying to capture. It’s not a number we’re trying to go for. Sales is really a fundamental result of foreign policy. We just have to understand what kind of workforce we’re going to need to prosecute those sales," Rixey said. "It’s nothing more than a tool for us to anticipate what we’re going to anticipate and work with."

The admiral also continued his defense of the speed of the FMS system, following up on comments made last month at a conference and an editorial featured in Defense News.

As to the jet sales, Rixey would not comment on the full status, but acknowledged media reports that the sales are "moving forward."