Travel agents could be skewing the census results by promoting tours abroad during this week's bonus school holiday, it was revealed yesterday. More than two-thirds of schools and several university faculties have closed so students and staff can carry out the survey. The Government conducts the census in March partly because residents are less likely to be abroad. But with tens of thousands of children on holiday, tour operators are cashing in. Agents said most flights to Bangkok, Cebu, Phuket and Kota Kinabalu were booked for the month. 'It's difficult to give a number, but it is a bit higher this March than normal,' said a Westminster Travel spokesman. Census and Statistics Commissioner Frederick Ho Wing-huen admitted some households would take advantage of the break to go abroad but said the number was negligible. 'Unless the householders are away for the full nine days [of the survey] we will still be able to catch them,' he said. The survey provides the most accurate, up to date information about Hong Kong's population enabling the Government to plan for health, social services, transport, housing and education.