Retail sales surged to their biggest monthly gain on record in March, and the seventh consecutive month of growth, according to a crucial indicator of retailers’ performance.

Thomson Reuters, which collected data from 28 chains on same-store sales, said Thursday, April 8, that sales increased 9.1% over the similar month last year, the biggest monthly gain since it began keeping records in 2000. Same-store sales are defined as stores that are open at least a year.

A couple of special factors muted the celebration, though. The results were robust this year because sales in March 2009, which declined 5%, were awful, and a relatively early Easter boosted sales momentum at the end of March.

Still, analysts said the numbers exceeded expectations. Chandi Neubauer, softline retail analyst at Majestic Research, based in New York, said, “We were expecting things to be pretty solid with the Easter holiday shifting the way it did. And I think it was better than solid.”

Though same-store sales in April will be denied its Easter bump, expectations by analysts are for a strong one-two punch from the combined months.

“I think a lot of the momentum is going to continue,” Neubauer said, “but it definitely won’t be near what we saw in March. But putting the two months together on a year-over-year basis should look pretty good.”

Please read a recent story on results from home sales and the services sector at InvestmentAdvisor.com.