George Strait, Kenny Chesney, Shania Twain and Toby Keith are among the artists whose greatest hits collections achieved multi-platinum milestones during the month of December, according to figures released Tuesday (Dec. 21) by the RIAA. Strait's recent double-disc 50 Number Ones is certified quintuple platinum for shipments of 5 million copies, and Chesney's Greatest Hits, released in 2000, is certified at 4 million. Twain's new Greatest Hits and Keith's Greatest Hits 2 are certified for shipments of 3 million and 2 million, respectively. Other multi-platinum certifications for the month include Tim McGraw's Live Like You Were Dying (3 million) and Brad Paisley's Mud on the Tires (2 million). Sara Evans received a platinum award for her 2003 album, Restless. Shipments of 500,000 copies resulted in gold certifications for Gary Allan's Used Heart for Sale, Brooks & Dunn's Greatest Hits, Vol. II, Johnny Cash's Unearthed and Lonestar's Let's Be Us Again.