Retailers, restaurants, and bars across the nation will be seeing plenty of green -- money, that is -- on St. Patrick's Day this year.

U.S. consumers will spend an estimated $3.76 billion on the holiday, which falls on Saturday, March 17, this year, according to the National Retail Federation's  annual Consumer Intentions and Actions Survey. This averages out to $34.89 per person -- almost a $7 increase from last year's average of $27.94.

It's little surprise that local Irish pubs and restaurants top the list for businesses that cash in  on St. Patrick's Day each year. Out of 9,027 consumers surveyed, 30.5 percent said they planned to celebrate the holiday by attending a party at their favorite restaurant or bar. Other popular ways of celebrating include making a festive dinner (33.9 percent), decorating a home or office (22.2 percent) and attending a private party (17 percent). Still, the most popular way of getting in on the festivities involves showing pride for the Irish, with 82.6 percent of consumers saying that they plan on wearing something green for St. Patrick's Day.

With the holiday falling on a Saturday this year, restaurants and retailers  have been gearing up for a long weekend of celebrating.

"We're always packed to the gills, from 8 a.m. on," said Marshall Robbins, restaurant manager at the Wheeltapper Pub, a popular St. Patrick's Day destination in midtown Manhattan. The restaurant and bar's sales typically double for the holiday, compared to a good night, Robbins said. Customers don't just spend money on alcohol; many come for the traditional Irish fare of corned beef, cabbage, and shepherd's pie that the Wheeltapper serves up.

In order to accommodate the larger crowds, the pub will be opening up its 2,500-square-foot patio and is stocking all the necessary goods. "We quadruple up on everything," Robbins said. In one day alone, he ordered 150 cases of beer.

Wheeltapper's location near the beginning of New York's famous St. Patrick's Day parade route will ensure a flow of people throughout the day on Saturday. Robbins predicted the biggest push to be around lunchtime. "There are probably going to be more families this year since it's on the weekend, and they will come early on," Robbins said. "Then later it will turn into regular drink-fest."

There are sure to be comparable crowds at pubs in many major cities. Danny Coleman, who is a manager at the Dubliner in Washington's Capitol Hill neighborhood, calls his pub's St. Patrick's Day "the best party on the east coast." He said he expects about 4,000 people to come through the door. "All in all, it's going to be a huge weekend," Coleman said.

The 33-year-old pub, which is owned and operated by a father-son team, takes over the ballroom of a neighboring hotel and has live music all day with bands playing on two stages. Coleman said the pub has been busy all week, with customers already starting the party early.

St. Patrick's Day also provides a boost to retailers. Risa Meyer, co-founder of Plum Party, a Long Island City, N.Y.-based online party supply and novelty gifts  store, said her St. Patrick's Day items have grown in popularity in recent years. "The glass shamrocks are very popular to use on tables and customers like the green confetti and green scalloped plates," she said.

According to the NRF, young adults will spend the most on St. Patrick's Day this year, with 18- to 24-year-olds expected to shell out $40.12, followed by 25- to 34-year-olds who will spend $39.04.