The top 10 artist in the music site for real-time and daily chart on July 12 showed the majority to be occupied by girl groups as there are 4 group mentioned while boy groups are nowhere to be seen.

However the offline album market shows a different story.

Group Super Junior that placed in the top 20 of music chart with their sixth studio album Sexy, Free & Single that was released on July 4 sold 220,000 copies within a week. Also JYJ's Junsu who is not included in the rankings sold over 100,000 copies with his first solo album Tarantallegra, released May 14.

Group Big Bang became the king of album sales in the first half of 2012 based on sales figure of their mini-album Alive, released in February, and special album Still Alive, which sold over a total of 400,000 copies.

The difference of boy group and girl group is striking as f(x)'s mini-album Electric Shock released on the 13th of last month sold 60,000 copies, SISTAR and T-ARA's mini-album released on June 28 and July 3 respectively sold 11,000 copies and 30,000 copies.

So then it seems boy group is stronger in album sales, while girl group sweeps the music chart.

Music industry experts state the reason being with the difference of music style and fandom between girl and boy groups.

Album distributor, Loen Entertainment's project leader stated, "Boy groups songs are typically bit difficult. It's because the music are generally focused on powerful performance, and these songs are difficult to be placed in the music chart that is generally used by people of different ages."

The representative added, instead boy groups retain more close fans consisting of students and female mania. And such differences are shown in album sales.

In the exception of girl group that have emerged as global stars such as Girls' Generation, 2NE1 there aren't that many girl groups that retains a larger mania base fans similar to boy groups. Girl group's music is generally enjoyed by various age covering teenagers to those in their 40s, however this doesn't lead to album sales.

A CJ E&M representative also showed a similar view.

"When we study the users of music sites girl group music is generally enjoyed by teenagers to those in their 30-40s and even up to 50s or more which is widely spread out, however boy group fans are generally in their teens to 20s. For boy idol groups the target group is clear which makes it easier to sell albums however is weak in the music charts," analyzed the representative.

In reality the music site users for example on Mnet.com studied the membership increase during the group comeback. When boy group's make their comeback the memberships only increase up to 100 however when girl group's make their comeback the membership is increased from 300 up to even 1,000.

Of course there are groups that are cannot be placed in this simple formula. Like group Big Bang that swept the entire top music charts each time they release their album. And girl group of Girls' Generation, 2NE1 are an exception to this as they display 'girl group power' with recording an average of 100,000 copies album sales.

This is because group's like Big Bang, Girls' Generation and 2NE1 have already build their own music style. Their fan base itself is different from other general group. They are groups that hold star power as they can directly affect the increasing number of memberships in music chart sites.