NEW YORK (CNN/Money) - The average price of a Manhattan apartment has topped $1 million for the first time, according to a new survey.

The average sale price for a Manhattan apartment rose to $1.05 million in the second quarter, up 4.9 percent from the first quarter and a whopping 20.9 percent from $866,970 a year earlier, according to New York-based real estate brokerage Douglas Elliman and appraisal firm Miller Samuel.

The median price, or mid-point of prices paid, rose 7.8 percent from the previous quarter to a record $674,000, indicating strong demand at the higher end of the market, the real estate firms said in their report.

The median price in Manhattan was almost 4 times the average U.S. median price for existing homes in May, according to the National Association of Realtors.

Luxury apartments in Manhattan have been selling briskly, boosted by a resurgence in the local economy, and a pickup in pay and bonuses on Wall Street.

Shrinking inventories have also helped lift prices to record highs, the firms said.

Although the number of listings climbed by 21.2 percent to 5,211 in the second quarter, that's still 14 percent below a year earlier, according to the survey.

It took about 105 days to sell a Manhattan apartment in the second quarter, a week longer than in the prior quarter, but shorter than the 142 days a year earlier.

The market also got a boost as mortgage rates fell to historic lows along with interest rates.