 But assuming that the precolonial population of Burma was relatively constant, the estimates of 40,000 to 60,000 of the "entire military" are not improbable, and are in line with figures given for the Burmese military between the 16th and 19th centuries in a variety of sources.The economy of Pagan was based primarily on agriculture, and to a much smaller degree, on trade.The growth of the Pagan Empire and subsequent development of irrigated lands in new lands sustained a growth in the number of population centres and a growing prosperous economy.