<prompt> Annual growth rate isCrude bih rate-Crude death rateCrude death rate-Crude bih rateCrude bih rate-Crude death rate x 100Crude bih rateCrude bih rate-crude death rate x 100Mid bih rate population  <response>: When crude death rate is substracted from crude bih rate , the net residual is current annual growth rate, exclusive of migration. Population growth rates like railway trains are subject to momentum. They sta slowly and gains momentum, once in motion, it takes time to bring momentum under control. Reference: Park;s textbook of preventive and social medicine, 23rd edition, pg no: 481 