The United States retail garden-center market contained roughly 16,000 independently operated companies in 2010 according to Research and Markets. The combined annual revenue for the lot of them is about $30 billion. Most garden centers are independently owned. There are some regional chains, but there is no national US garden center chain, unlike in the UK where there are several. However, both of the largest home improvement stores in the US—Lowe's and The Home Depot—refer to their gardening departments as garden centers and larger hardware stores have "Lawn and Garden" departments.</ref>