The million-dollar listing is a growing phenomenon. According to a new Trulia report analyzing home values nationwide, the share of single-family homes sporting seven-figure values has grown 7.6 percent over the past year alone, and doubled since 2012, increasing from 1.5 percent to 3.6 percent of all homes on the market.

Despite the market’s recent cool-down, home values continue to rise, appreciating an average of 7.6 percent in just the last year alone, underscoring the continued affordability crisis. This has swelled the ranks of million-dollar neighborhoods, where the median home value is more than $1 million. Now, 838 of the 15,100 neighborhoods included in the study have that distinction.

Not surprisingly, the phenomenon proliferates in coastal areas, especially California. Roughly two-thirds of such neighborhoods can be found in the Golden State, where 29 percent of all neighborhoods have a median value north of $1 million. The top four states in the nation for such pricey real estate—California, as wall as New York, Florida, and Washington—contain 82.8 percent of such neighborhoods. Colorado, due to expensive areas around Boulder, rounds out the top five.

The growth of million-dollar neighborhoods has accelerated over the last year, when 105 areas earned that distinction. The Trulia report found that of cities with at least 10 such neighborhoods, 8 were in coastal California. Boulder, Colorado, and Brookline, Massachusetts, also made the list.

The phenomenon is especially prevalent in the Bay Area. In San Francisco last year, seven new million-dollar ’hoods, including South of Market, Portola, Ingleside, and Fisherman’s Wharf, joined the club of 80 that already have million-dollar median values. Only 15 neighborhoods in the city have median homes values below seven figures, and there’s little relief in the surrounding region; many of the smaller Bay Area cities contain similarly high-priced housing. In Oakland, 20 of the 290 larger neighborhoods passed into million-dollar territory last year, and in San Jose, the percentage of million-dollar homes rose from 55.7 percent to 70 percent last year.

Million-dollar neighborhoods aren’t limited to California. In Honolulu, for example, nearly 20 percent of the housing stock is now valued at more than $1 million. Other metro areas saw their first such seven-figure neighborhood. In Austin, Barton Creek’s median value appreciated from $935,000 to $1.02 million. In Indianapolis’s Crows Nest, the median value jumped from $977,000 to $1.07 million, while Lily-Almy Pond, an area in Newport, Rhode Island, crocked the ceiling, reaching $1.15 million median value.

The report predicts other neighborhoods will soon appreciate to a similar value, including Birch Park Finger Streets in Fort Lauderdale, Florida; Stonegate in Renton, which is southeast of Seattle; and Cherokee Park in Sandy Springs, a suburb of Atlanta.