PORTLAND (AP) – Big-box stores may have been a late coming to Maine, but their impact has been felt at most levels of retail business in the state, census estimates recently released suggest.

While the number of retail businesses in Maine dropped slightly from 1997 to 2002, sales and employment in the sector both increased during this period, when big-box retailers such as Wal-Mart and Target were expanding their presence.

“We’ve had a lot of the big-box stores come along, and some of the smaller stores have gone out, sometimes as a result,” said Glenn Mills, senior economic analyst with the Maine Department of Labor.

Wal-Mart, Home Depot, Sam’s Club and other large stores expanded nationally in the 1980s, but they did not start coming to Maine en masse until the 1990s. The trend continues now with stores like Lowe’s and Kohl’s popping up around Maine.

The five-year update includes data from 1997 and 2002 and represents the Census Bureau’s most detailed look at the state’s retail sector. It’s part of a broader look at the U.S. economy the bureau does every five years.

According to the report, there were 7,074 retail businesses in Maine in 1997, representing $12.7 billion in sales and employing 72,897. In 2002, the number of businesses dropped to 7,050.

Tom Yake, a Kennebunk-based retail analyst with Yake & Associates Inc., said he thought big-box stores definitely hurt small retailers.

“They have so much buying power with the vendors that the small Maine retailer just can’t compete,” Yake said. “I think there’s been a number of Maine retailers that have gone out of business.”

Retail is seen as an important sector in Maine’s economy. According to the Labor Department’s February estimates, 86,300 people worked in retail out of a total work force of 594,300, or 15 percent of Maine’s workers.

However, Mills noted that many of the people employed in retail are part-timers, and that they choose to work less than 40 hours a week.

“For many people, a full-time, 40-plus-hour-a-week job, is not what’s called for,” said Mills. “You have students, you have families where one parent is the primary breadwinner and the other is getting some extra money.”

According to the Census Bureau, policymaking groups in the federal government use the information from the economic census to measure the success of different programs and policies.

State and local governments use it to examine business activities and tax bases, as well as to develop programs to attract businesses.