Google Inc. gained search market share in the United States for the 10th consecutive month in May, while rivals managed to hold stead, a market research firm said.

Google's share inched up 1 percent from April to 44.1 percent, ComScore Networks said. Second-place Yahoo and third-place Microsoft MSN, meanwhile, saw their shares remain relatively unchanged month-to-month at 27.9 percent and 12.9 percent respectively.

Year-to-year, Google was the only one of the three rivals to post a gain in market share. Google rose 6.6 percent from the same month a year ago, while Yahoo and MSN dropped 2.2 percent and 2.3 percent, respectively.

In other ComScore findings, Americans conducted 7.4 billion online searches in May, up 12 percent from the previous month. Social-networking site MySpace.com, which entered the search market for the first time last month, maintained its sixth-place ranking with a 0.7 percent share, and Google and Yahoo continued to dominate the toolbar search market with shares of 49.1 percent and 46.2 percent, respectively.