US senators received a classified briefing on increased UFO sightings earlier this month.

An INSIDER analysis found that reported UFO sightings in the US peaked in 2014.

Since then, they've been steadily decreasing.

More UFO sightings were reported in July 2014 than any other month this decade.

But this June, sightings are up 50% over last year at the same time, possibly signaling that another upward trend is beginning.

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In early June, three US senators were given classified information by the Pentagon on UFO sightings — the latest group of government officials to be briefed on UFOs. It came amid news that US Navy pilots were reporting increased encounters with UFOs.

But an INSIDER analysis of UFO sightings reported by civilians found that sightings have been steadily decreasing for the past five years, after a peak in 2014.

INSIDER analyzed data from the National UFO Reporting Center (NUFORC), a rural Washington-based organization that has been collecting reports of UFO sightings since 1974.

Approximately 130,000 reports have been made — via either a 24-hour hotline or an online form — over the center's 45-year history, including around 60,000 in the last decade alone.

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Summer months are when the most UFOs are glimpsed, and July 2014 was host to the highest number of reported sightings all decade. According to Cassidy Nicholas, the chief archivist of the Mutual UFO Network (MUFON), a large volunteer-run organization devoted to investigating sightings, it's because that's when people spend more time outdoors, and tend to notice things in the sky. Since then, there's been a steady decline in reports of UFOs.

Most UFO researchers and fanatics aren't too fazed by lulls in sightings. "We've seen this throughout history so it gives us investigators a little breathing room to better prepare ourselves for the next wave," Chuck Zukowski, a self-described "ghostbuster for aliens," told INSIDER.

Zukowski believes that high concentrations of UFO sightings — or "flaps," as they're called by the UFO community — coincide with major shifts for humanity, like world wars or the dawn of new technology. He told INSIDER that 2014 may have been a flap: He investigated more sightings and cattle mutilations that year than at any other time.

Recently publicized sightings made by US Navy pilots, which coincide with the 2014 peak, have described cylindrical objects traveling at hypersonic speeds and defying the logic of aeronautical flight. Civilian reported sightings, on the other hand, are more abstract. The majority of the UFO shapes described in the analysis were categorized as "light," "round," or "fireball."

NUFORC's long-time director, Peter Davenport, says all reports aren't given the same credence. Davenport told INSIDER that some reports draw skepticism — those submitted by anonymously, for instance — and says he tends to put more stock in the ones reported by public servants or pilots, or ones that include photographs or radar evidence.

People have often mistaken aircraft and other terrestrial phenomena for alien spaceships. In 2015, Californians took to social media and called law enforcement en masse when a streak of bright light cut through the night sky. The "UFO" turned out to be a test missile launched by the US Navy.

Despite the downward trend since 2014, reported sightings this month are already 50% higher than they were last June. It could be the start of another flap — or it could be nothing at all.

Read more:

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