Google Inc enjoyed one of its biggest monthly gains in U.S. Web search market share in October, building on consistent gains over the past two years, according to industry data out on Wednesday.

Market research firm comScore Inc said Google's core Web search properties captured 58.5 percent of the U.S. market in October, up from 57.0 percent in September.

The top five providers of Web search all showed at least 5 percent growth in the number of searches in October. Yahoo Inc was number two after Google, followed by Microsoft Corp, IAC/InterActiveCorp's Ask.com and Time Warner Inc's network of sites, including AOL.