When it comes to scoring hits, Flo Rida has it down to a science. In the Aug. 25 issue, the rapper's latest single, "Whistle," ended the reign of Carly Rae Jepsen's "Call Me Maybe" atop the Billboard Hot 100, climbing 3-1. Its total digital sales stand at 1.9 million, according to Nielsen SoundScan.Though "Whistle" loses the No. 1 spot this week to Taylor Swift's "We Are Never Ever Getting Back T