However, in 2004, 98% of the population already has access to an improved water source, a very high level for a low-income country. This has been achieved through the construction of hand pumps with the support of external donors. Bangladesh has a low level of cost recovery due to low tariffs and poor economic efficiency, especially in urban areas where revenues from water sales do not cover operating costs. Only 56% of the population was estimated to have access to adequate sanitation facilities in 2010. But a new approach to improve sanitation coverage in rural areas, namely the community-led total sanitation concept, was introduced in Bangladesh and is credited for having contributed significantly to the increase in sanitation coverage. The government has adopted policies that could remedy the challenges in the sector. These include the "National Policies for Safe Water Supply and Sanitation", "National Water Management Plan", the "National Policy for Arsenic Mitigation" which gives preference to surface water over groundwater and the "National Sanitation Strategy of 2005". These policies emphasize decentralization, user participation, the role of women, and appropriate pricing rules. In 2015, 87% of the population had access to "improved" water, and the figure was identical to rural and urban areas. In 2015, there were still around 21 million lacking access to "improved" water. Regarding sanitation, 61% of the total population had access to "improved" sanitation, or 58% and 62%, in urban and rural areas, respectively. Since arsenic was discovered in Bangladeshi groundwater in 1993, the share of population with access to safe drinking water had to be adjusted downward. According to the Joint Monitoring Program for Water Supply and Sanitation of UNICEF and the World Health Organization (WHO), access to an improved source of water supply increased only slightly from 77% in 1990 to 81% in 2010, whereas coverage of improved sanitation increased from 39% to 46% during the same period. Estimates of access to an improved source of water supply is greatly affected by the presence of arsenic in groundwater, which is estimated to affect 27% of all wells and is subtracted from the figures obtained by solely measuring the level of access to infrastructure. Without taking into account the presence of arsenic, 99% of the urban population and 97% of the rural population actually had access to an improved source of water supply according to the Demographic and Health Survey of 2004, which is an unusually high level of access for a low-income country. In urban areas, access is broken down as follows:   In rural areas the breakdown is:   Rainwater harvesting, although practised in Bangladesh, was not included in the survey.