Newly released US State Department cables indicate that Donald Trump, a self-styled political outsider, was a ghost on the international diplomatic stage as well in the years before he became the most powerful man in the world.

In response to a Freedom of Information Act request for mentions of Trump from January 2010 to early June 2016, a month before he clinched the Republican nomination, the State Department said it discovered a total of just 16 relevant communiques from its embassies or consulates abroad — and 11 of those were translations of public German media reports about the 2016 U.S. election.

During a similar period prior to the 2008 election, then-Sen. Barack Obama's name came up 145 times and the name of his opponent, Sen. John McCain, appeared 139 times in diplomatic cables, according to State Department communications published online by WikiLeaks in 2010. (Trump is mentioned an additional 13 times in the WikiLeaks cable database, which covered 2003 to 2010 — six of those mentions were transcripts of Israeli media reports.)

That the man who would become president was so rarely mentioned, despite high-profile business projects around the world, did not come as a shock to Cameron Hume, former ambassador to Indonesia and a career foreign service officer.

“It doesn’t really surprise me. We don’t generally report on private American citizens,” Hume said, adding that most American businesses do not involve the US government in their foreign projects, at least unless things go sideways.

“If they’re happy, they don’t talk to you. If they’re unhappy, that’s when they might get [the embassy] involved,” he said.

When it came to Trump as a presidential candidate in 2015 and the first half of 2016, another former ambassador, who requested anonymity to discuss diplomatic protocol, said senior US officials serving abroad would likely have tried to avoid discussions about the ongoing election as best they could, based on longstanding tradition and decorum.

"It doesn't surprise me that there wouldn't be a lot of chatter in the cables about him, because most of us wouldn't engage in that conversation," the ex-official said. "Even if someone came up to you and said, 'What do you think of Trump?', you just don't engage, because we're career professionals. That's not what we're supposed to do."

Hume, who left the State Department in 2010, said he does not doubt the election came up in discussions with foreign officials, but that likely happened in social settings and were not considered anything officials felt obligated to report.

In March 2016, Reuters reported that foreign diplomats were raising alarm "in private conversations" with US officials about Trump's incendiary campaign rhetoric, but a source familiar with that reporting said those conversations took place at high levels in offices in Washington, DC, and therefore would not be included in the international cables.

Here's what did make the cables: