At 99, the late Henry Kissinger still worked 15 hours a day and flew around the world on business trips

• Even in his old age, Henry Kissinger was still working around the clock.
• The controversial statesman told CBS News that at 99, he was  clocking 15-hour work days.
• Former Google CEO Eric Schmidt says Kissinger '"works harder than a 40-year-old."

Back in May, the late Henry Kissinger was on the cusp of becoming a centenarian, but he was still working around the clock.

"I work about 15 hours a day," he told CBS News in an interview that aired on May 7, several weeks before his 100th birthday.