The Gaon Chart is the national chart of South Korea and is intended to be the equivalent of Oricon in Japan and Billboard in the United States.
The Gaon Album Chart are a set national charts that ranks the best-selling albums, including mini-albums and singles, in South Korea, provided by the Korea Music Content Industry Association. The charts are made up of charts tracking domestic album sales, international album sales and a combined overall album sales in weekly, monthly and year-end format.
KPOPSALES shared the following information on September 19th:
*** Kim Jaejoong released 2 Mini-albums “I” & “Y”.
“I” Mini-album was released on January 17th, following by the Repackage Mini-album “Y” on February 26th, that contains the same songs from I with two extra tracks ”Only Love” & “Kiss B” and two instrumental tracks, this mini-album was released to please the high demand and the limited stock of I Mini-album. According to CJeS both mini-albums are sold out.
*** XIA Junsu released his 2nd Album “Incredible” on July 15th.
*** In the First half of 2013, CJeS ranked at 4th place with 9%, their sales included only Kim Jaejoong’s Mini-albums “I” & “Y” (Link)
*** On September 19th, CJeS’s Cumulative Sales is ranking at 3rd place, it includes Kim Jaejoong’s Mini-albums “I” & “Y” and XIA Junsu’s 2nd Album “Incredible”