If there’s one bright area area in U.S. mobile handset sales, it’s the smartphone segment, according to a report released today by the NPD Group, which looked at sales in the U.S. for the period from January to July 2008. During that period, overall mobile-phone revenues and sales declined, however, smartphone sales jumped to 9 million units, representing a $1.7 billion market, an increase of 71 percent. BlackBerry-maker Research In Motion maintained its position at the top, while Apple (NSDQ: AAPL) skyrocketed to second place, displacing HTC, which completely fell of the list of the top five. Release.

More highlights:

—Ranking: The top five handset makers for the seven-month period were: RIM; Apple; Palm; Samsung and Motorola (NYSE: MOT). RIM (NSDQ: RIMM) and Palm (NSDQ: PALM) both saw consumer unit-sales gains, posting growth of 24 percent and 9 percent, respectively.

—Marketshare: Smartphones represented 19 percent of all handset purchases compared to just 9 percent for the same period last year. Ross Rubin, NPD’s director of industry analysis: “Declining prices, streamlined form factors, and consumer Internet connectivity have begun to bring into the mainstream devices that once appealed only to mobile professionals.”

—Prices fall: The average price of a smartphone sold in the time period was $185, decreasing 7 percent from $199 during the same period last year.