Information from the Statistics and Census Service (DSEC) indicated that the total population was 640,700 as at end-March 2015, an increase of 4,500 quarter-to-quarter; female population (324,200) accounted for 50.6% of the total. There were 1,711 live births delivered in the first quarter of 2015, a decrease of 375 or 18.0% quarter-to-quarter. Male babies totalled 902 and the sex ratio at birth stood at 111.5, corresponding to 111.5 male babies per 100 female babies, higher than the normal sex ratio at birth (102-107) confirmed by the United Nations. Meanwhile, mortality totalled 536, an increase of 49 quarter-to-quarter; the top three underlying causes of death were Neoplasms (184), Diseases of the Circulatory System (139) and Diseases of the Respiratory System (92). In the first quarter of 2015, there were 2,639 Chinese immigrants, up by 995 quarter-to-quarter. Individuals granted right of abode totalled 600, a slight increase of 3. Non-resident workers totalled 174,924 at the end of the first quarter, up by 4,578. A total of 952 cases of marriage registration were recorded in the first quarter, down by 64 quarter-to-quarter.