Research outfit The Leading Question, in conjunction with Music Ally, studied the online habits of more than 1000 music fans and found the overall percentage of people swapping songs regularly has gone down significantly since the last time the company researched the subject two years ago. In this case, “regularly” is defined as sharing songs every month.

For example, in Dec. 2007 22 percent of those surveyed reported regular song trading. However in Jan. 2009 that figure diminished to 17 percent, a comparative drop of nearly a quarter.

The new survey also reports the biggest drop was in the 14-18 year olds, the most active age group when it comes to song-sharing. The December 2007 findings reported 42 percent of this demo traded songs monthly, but in January 2009 that figured had dropped to just 26 percent.

However the survey also points out that the percentage of United Kingdom fans who have ever shared a song had increased from 28 percent in Dec. 2007 to 31 percent in Jan. 2009.

The survey credits the reduction in song-swapping by U.K. teens to the increased availability of streaming, and cites social sites like YouTube and MySpace as the reasons why, saying 65 percent of teens are streaming music from their pages on social-networking sites. What’s more, the number of 14-18 year-olds listening to streamed music is almost twice the number of music fans overall with 31 percent of the teen demo listening to streams compared with 18 percent of all fans.

But that doesn’t mean teens suddenly became copyright-friendly. The same report indicates more fans are sharing burned CDs among friends and are distributing tracks, not by sharing them, but by “bluetoothing” music.

Decreases in the number of teens sharing songs while, at the same time, increases in listening to streams mirrors what P2P defenders were saying about much of the song-trading going on in the early days of the original Napster – that downloaders were “sampling” or previewing songs before purchasing.

With streaming growing more prevalent every year, those looking for a taste of a song or CD before making a purchasing decision are less apt to pirate music than their counterparts who consider P2P networks as a way to get free music and rip off the labels.

Click here for The Leading Question / Music Ally survey report.