South Africa\'s population census ends on Monday. Country Statistician-General said Statistics South Africa (Stats SA) is embarking on a \"mop-up phase\" as Census 2011 comes to a close. \"Operations on the ground indicate that there are households that we have not counted,\" Pali Lehohla Monday told a media briefing in Pretoria. However, the statistician-general was confident about the progress made to date during the national population and housing count. He said the 156,000 field staff visited 98.8 percent enumeration areas during the past 21 days. Lehohla said the focus for the statistical agency now moves to the payment of fieldworkers, collection of all questionnaires, and reverse logistics that will kick start data processing. The payment will start from November 10. \"We sent out more than 20 million questionnaires, now we got to get them back so we can start data processing,\" Lehohla said. According to United Nations (UN), the population census is \"the total process of collecting, compiling, evaluating, analyzing and publishing or otherwise disseminating demographic, economic and social data pertaining, at a specified time, to all persons in a country or a well-defined part of the country.\" Population data obtained during census informs decision-making, government and private sector to deal with social issues. All aimed at national development and economic growth. Lehohla said as Stats SA embarks on mop-up, the statistical agency will escalate its enforcement against those who refuse to be counted. To date, Lehohla said there were 16,000 refusals that had been registered during the population and housing census around the country. As Stats SA embarks on data processing, Lehohla announced that an independent team will go onto the field to conduct Post Enumeration Survey, a quality check exercise that determine among other things the census coverage and measure the undercount. \"What we are certain about is that census 2011 will be able to give us population trends, demographic trends, the level internal migration, the income levels of our country, and many other aspects like fertility and mortality,\" Statistician-General said. Census 2011 results will come out in November 2012.