Updated

The sci-fi series "The X-Files" popularized the saying "the truth is out there." And in the past 15 years, thousands of UFO sightings across the United States show a lot of people are still looking.

A new list of the top cities in the U.S. that have had UFO sightings from 2001-2015 has been published, with Phoenix topping the list, according to a story in the Syracuse New Times.

The data is pulled from the book "UFO Sightings Desk Reference: United States of America 2001-2015," written by Cheryl Costa and Linda Miller Costa. Published in March 2017, the book compiles "data and analysis for 100,000+ sightings of unidentified flying objects reported by individuals during the first 15 years of the 21st century."

'UFO' SPOTTED OVER YELLOWSTONE VOLCANO?

Costa noted that Phoenix may be the most prevalent place in the U.S. for UFO sightings, perhaps due to the Phoenix Lights phenomena two decades ago.

In 1997, there were two events that occurred in Phoenix, Arizona, and Sonora, Mexico. Thousands of witnesses say they saw a formation of five lights in a V-shape, producing no sound and a triangular formation of lights. The U.S Air Force claimed the second group of lights were flares dropped from a A-10 Warthog aircraft.

In addition to Phoenix, Las Vegas, Seattle, Chicago and Portland round out the top five cities on the list.

Below is the list of 25 most sightings across U.S. cities.

City UFO Sightings
Phoenix 929
Las Vegas 639
Seattle 616
Chicago 562
Portland 528
Los Angeles 525
Tucson 480
San Diego 477
Houston 466
Denver 429
Austin 426
New York City (Manhattan) 418
Orlando 390
Springfield 380
Albuquerque 376
Miami 375
Philadelphia 338
San Antonio 334
Columbus 327
Jacksonville 326
Sacramento 316
San Francisco 310
San Jose 308
Myrtle Beach 305
Dallas 294
Kansas City 294