 This is a ratio of 1 in 7—significantly less than the historical average before 1996 of 1 in 4.Since the fatality rates on Everest have dropped considerably, accounting for the volume of climbers in 1996 compared with previous years, 1996 was statistically a "safer"-than-average year.In May 2004, Kent Moore, a physicist, and John L. Semple, a surgeon, both researchers from the University of Toronto, told "New Scientist" magazine that an analysis of weather conditions on 11 May suggested that atmospheric oxygen levels fell by an additional 6%, resulting in a further 14% reduction in oxygen uptake.