Task: Question Answering
Input (English): Passage: The first true estimate of the population of Bolivia came in 1826, which 997,427 inhabitants were estimated. This number was calculated from the 1796 census organized by Francisco Gil de Taboada, which consisted of several Bolivian cities. The first modern census was completed in 1831, and ten have been completed since then. The organizer of Bolivians censuses has changed throughout the years—Andrés de Santa Cruz (1831), The Bolivian Statistical Office (1835, 1854, 1882), The Bolivian Statistical Commission (1845), The National Immigration Bureau and The Statistics and Geographic Propaganda (1900), and The Department of Statistics and Censuses (1950)—with the INE conducting the census since 1976. The national census is supposed to be conducted every ten years, however, the 2012 census was late because of "climatic factors and the financing." The 2012 census data was conducted on 21 November 2012, in which 10,027,254 inhabitants were in the country. The estimated cost of the census was $50 million. 
Question: How many years passed between the first and last census organized by the Bolivian Statistical Office? 
Answer type: Number 
Output (English): 47.