 Complete the following phrase:  Prior to Beamons jump, the world record had been broken thirteen times since 1901, with an average increase of 6 cm and the largest increase being 15 cm 6 in.. In the years following the jump, the mark was considered unbeatable. It took 12 years for another human being to jump 28 feet, much less 29. His world record stood for 23 years until it was finally broken in 1991 when Mike Powell jumped 8.95 m at the 