The President Mrs Pratibha Devisingh Patil today launched the second phase of enumeration gathering details of every resident of the country. Speaking on the occasion, she called upon people to take part whole heartedly in the census operation. Mrs Patil said it is a national duty. Home minister P Chidambaram and minister of state Gurudas Kamat and census commissioner C Chandramouli were present on the occasion.Yesterday, President released a commemorative postage stamp on census 2011 at Rashtrapati Bhavan. The nearly three-week-long exercise will end on 28th of this month providing a first-hand data on the demography and population of the country. Details like literacy level, marital status, disability and woman's fertility will be recorded for the first time. Apart from using modern technology like GIS to mark houses, more comprehensive questions have been framed to gather an exhaustive data.