While considerably higher than earlier and more widely accepted estimates of Khmer Rouge executions, the Documentation Center of Cambodia (DC-Cam)'s Craig Etcheson defended such estimates of over one million executions as "plausible, given the nature of the mass grave and DC-Cam's methods, which are more likely to produce an under-count of bodies rather than an over-estimate." Demographer Patrick Heuveline estimated that between 1.17 million and 3.42 million Cambodians died unnatural deaths between 1970 and 1979, with between 150,000 and 300,000 of those deaths occurring during the civil war. Heuveline's central estimate is 2.52 million excess deaths, of which 1.4 million were the direct result of violence. Despite being based on a house-to-house survey of Cambodians, the estimate of 3.3 million deaths promulgated by the Khmer Rouge's successor regime, the People's Republic of Kampuchea (PRK), is generally considered to be an exaggeration; among other methodological errors, the PRK authorities added the estimated number of victims that had been found in the partially-exhumed mass graves to the raw survey results, meaning that some victims would have been double-counted.