Longevity claims may be subcategorized into four groups: "In late life, very old people often tend to advance their ages at the rate of about 17 years per decade ... Several celebrated super-centenarians (over 110 years) are believed to have been double lives (father and son, relations with the same names or successive bearers of a title) ... A number of instances have been commercially sponsored, while a fourth category of recent claims are those made for political ends ..." The estimate of 17 years per decade was corroborated by the 1901 and 1911 British censuses. "Time" magazine considered that, by the Soviet Union, longevity had been elevated to a state-supported "Methuselah cult". Robert Ripley regularly reported supercentenarian claims in "Ripley's Believe It or Not!", usually citing his own reputation as a fact-checker to claim reliability.