Gen Fukunaga, the president and CEO of Funimation, has praised Clamp as being "one of the most acclaimed groups of artists in Japan". According to Charles Solomon, a journalist for "The New York Times", Clamp "ranks among the most successful creators of manga ... in Japan and the United States". Dallas Middaugh, associate publisher of Del Rey Manga, stated that Clamp was an integral part of "manga explosion" that has been occurring in the United States over the past few years. He also praised the group's artwork and storytelling style as having "struck a strong chord with male and female manga readers". The group was placed third after the winner for the Shogakukan Manga Award in the Children's category in 1999. Their work "Cardcaptor Sakura" won the Seiun Award for best manga in 2001. Almost 100 million Clamp "tankōbon" copies have been sold worldwide as of October 2007. Various of their selling series include "xxxHolic" and "Tsubasa: Reservoir Chronicle" that have sold over eleven million and twenty million volumes, respectively.