A tribe of Neanderthal hunter gatherers population 100 is subject to resource limited growth in a river delta area 1000 hectares. In the early development of their civilization, the population is expected to reach 1000 after how many years? Assume that the specific growth rate is 0.55/year, the half saturation constant is 0.5, the respiration rate is 0.5/year, the yield constant is 0.5 and the initial substrate concentration is 1000 kg/hectare?