Things that go bump in the night aren't just for children anymore.

According to a survey conducted by the National Retail Federation 34 percent of adults will dress up for Halloween this year and the holiday's popularity is continuing to grow among young adults. Almost two-thirds (62.8 percent) of 18-24 year olds will wear a costume this year.

&#8220Knowing the competitive spirit that exists among young adults when it comes to sporting the best Halloween costume, many retailers have altered their merchandise assortment to appeal to this enthusiastic consumer base,” states Phil Rist, vice president of strategy for BIGresearch, an online marketing research firm that conducted the NRF's survey.

The survey measured consumer behavior and shopping trends of 8,001 consumers from Sept. 6 to Sept. 13.

The NRF estimates that consumers will spend $4.96 billion this spook season. Last year ghost and goblin lovers spent $3.29 billion.

Although Halloween is growing, it still rates behind traditional gift-giving holidays such as Christmas, Valentine's Day and Easter. Halloween is ranked sixth behind Father's Day ($9.01 billion spent this year).

&#8220Consumers see Halloween as a seasonal celebration to bridge the gap between the end of summer and the winter holidays,” said Tracy Mullin, President and CEO of NRF.

&#8220Halloween offers a little something for everyone and, this year, people of all ages will be joining in the fun.”

85.3 percent of 18-24 year olds will be celebrating Halloween this year, up from 66.8 percent last year.

&#8220Halloween has especially exploded among young adults who are celebrating with large parties and elaborate costumes, driving spending and bringing good news for retailers,” said Phil Rist, Vice President of Strategy for BIGresearch.

&#8220With the holiday falling on a Tuesday this year, young adults may begin participating in Halloween activities the weekend before and spend several days celebrating.”

Among children dressing up this season, princess costumes are the top choice for the second year in a row at 11.5 percent. Pirates (5 percent), witches (4.8 percent), Spider-Man (4.4 percent), and Disney princess characters (3.1 percent) round out the top five.

17.5 percent of adults will dress as witches this year, followed by pirates (3.7 percent), vampires (3.7 percent), cats (2.6 percent), and clowns (1.8 percent).

&#8220This year pirate costumes are popular among consumers of all ages, due largely to the widespread success of the Pirates of the Caribbean franchise,” said Rist. &#8220Knowing the competitive spirit that exists among young adults when it comes to sporting the best Halloween costume, many retailers have altered their merchandise assortment to appeal to this enthusiastic consumer base.”