Since 1955 we have reported the geographic variations of reproduction rates by prefectures in Japan. This report dealt with the results of the study for the years of 1975 and 1980. Method of estimating the number of births and female population by age was ameliorated and reported in detail in the separate report (Nanjo et al . 1987). In 1975 the prefectures where NRRs were kept above replacement level were 6, Okinawa, Nagasaki, Iwate, Fukushima, Miyazaki, and Shiga, and in 1980 only one, Okinawa. The highest NRR was observed in Okinawa for both 1975 and 1980, 1.4034 and 1.1340, and the lowest in Tokyo, 0.7763 and 0.6846 respectively. Geographic variations, which had changed due to the marked increments of NRRs in industrialized urban prefectures at the time of second baby-boom around 1970, have been returning to the former pattern of smaller NRRs in industrialized urban prefectures and larger ones in rural agricultural prefectures as observed in 1960. Distinct differences were noticed in age patterns of birth rates in different geographical area. Rural prefectures along the Japan Sea showed a pattern of higher rates in age 20's and lower rates after age 30's while prefectures having large cities with millions population showed the patterns of lower rates in 20's and higher rates after 30's. Age patterns of birth rates are closely related to the levels of NRR and prefectures with larger NRR have the former pattern, rural type, and those with smaller NRR the latter, urban type. The strong influence on NRR is now attributed to the fertility of age 20's rather than to the total fertility of ages from 15 to 49. Intrinsic vital rates were also calculated and given in the text .
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