<prompt> To achieve Net reproduction rate NRR of 1, couple protection rate should be -50505560  <response>: - couple protection rate is an indicator of the prevalence of contraceptive practice in the community. - CPR is defined as the percent of eligible couples effectively protected against child bih by one or other approved methods of family planning. - demographers are of the view that the demographic goal of NRR1 can be achieved only if the CPR exceeds 60. Reference : Parks textbook of preventive and social medicine, 23rd edition, pg no:493 p 