Models in costumes from Walt Disney Studio's "Maleficent", Marvel's "Avengers" and more at a Disney Halloween Fashion Show,  Oct. 1, 2014, in Glendale, Calif. (Photo by Jordan Strauss/Invision for Disney Consumer Products/AP Images)

Models in costumes from Walt Disney Studio’s “Maleficent”, Marvel’s “Avengers” and more at a Disney Halloween Fashion Show, Oct. 1, 2014, in Glendale, Calif. (Photo by Jordan Strauss/Invision for Disney Consumer Products/AP Images)

Halloween may have evolved from spooky origins in England, Ireland and Scotland — where the Celts believed the dead could walk among the living during the transition between the seasons — but in America, Halloween is now more about candy and costumes than anything else.

Once darkness falls, children dress up and walk from house to house, calling out, “Trick or treat,” each time front doors open. They’re usually rewarded with small pieces of packaged candy. Long ago, homemade treats were handed out but today’s parents worry about such offerings since they are more easily tampered with than store-bought candy.

Americans are expected to spend upwards of $7.4 billion on the candy, which comes in special packages for the holiday, as well as on costumes and home decorations, according to the National Retail Federation (NRF). The trade association also says more than two-thirds of Americans will buy Halloween costumes this year.

“With the holiday falling on a Friday this year, we fully expect there will be a record number of consumers taking to the streets, visiting haunted houses and throwing unforgettable celebrations,” said NRF President and CEO Matthew Shay, in a press release.

The average person will spend $77.52 this Halloween, up about $2 from last year, according to NRF.

Groot from "Guardians of the Galaxy" makes 2014's list of most popular Halloween costumes. (Marvel Cinematic Universe)

Groot from “Guardians of the Galaxy” makes 2014’s list of most popular Halloween costumes. (Marvel Cinematic Universe)

And this isn’t just child’s play. More money — $1.4 billion compared to $1.1 billion — will be spent on adult costumes than on children’s costumes.

Hypable reports that Fandago, the movie ticket service, says Maleficent from the Angelina Jolie film of the same name, Katniss from The Hunger Games, and Mystique from X-Men: Days of Future Past, are the most sought-after looks for women.

Men are dressing up as Groot from Guardians of the Galaxy, Captain America, and Ninja Turtles.

Mashable asked the folks at Google Trends which costumes people searched for the most this Halloween. Their findings suggest many children will be dressed up as characters from the movie Frozen because Elsa, Olaf and Anna all made the Top 10 list.

The majority of the most popular costumes is inspired by popular films but at least one, Assassin’s Creed, was inspired by a video game.

Here’s the complete list:

  1. Elsa (Frozen)
  2. Olaf (Frozen)
  3. Maleficent
  4. Ninja Turtle (Teenage Mutant Ninja Turtles)
  5. Anna (Frozen)
  6. Black Widow (The Avengers)
  7. Captain America (The Avengers)
  8. Groot (Guardians of the Galaxy)
  9. Dog spider (spider costume for a dog)
  10. Assassin’s Creed (video game)

Although Halloween is one of the most popular holidays of the year, Americans spend much more money on other significant days, including Christmas, Mother’s Day, Father’s Day, Valentine’s Day and Easter.