General note on the data
The data presented in the following statistical table are accompanied by definitions, sources and explanations of symbols. The tables are derived from many sources and thus will inevitably cover a wide range of data quality. Official government data received by the responsible United Nations agency have been used whenever possible. In the many cases where there are no reliable official figures, estimates made by the responsible United Nations agency have been used. Where such internationally standardized estimates do not exist, the tables draw on other sources, particularly data received from the appropriate UNICEF field office. Where possible, only comprehensive or representative national data have been used.
Data quality is likely to be adversely affected for countries that have recently suffered from man-made or natural disasters. This is particularly so where basic country infrastructure has been fragmented or major population movements have occured.
Data for life expectancy, total fertility rates, crude birth and death rates, etc. are part of the regular work on estimates and projections undertaken by the United Nations Population Division. These and other internationally produced estimates are revised periodically, which explains why some of the data will differ from those found in earlier UNICEF publications.
Several changes have been made to the statistical tables in this issue of the report. In table 2, the 'total goitre rate' is no longer included alongside the 'percentage of households using adequately iodized salt', as an indicator of progress made in eliminating iodine deficiency, based on a 1999 decision of WHO, UNICEF and ICCIDD. Also in table 2, 'vitamin A supplementation coverage rate' has been added as an indicator of progress made in eliminating vitamin A deficiency.
The second major change concerns the data on maternal mortality in table 7. Last year, two columns of data were published on maternal mortality - the 'reported' and 'adjusted' rates. The first column included the most recent estimates reported by national authorities, and the second column included these rates adjusted for misclassification and underreporting of maternal deaths. This was done to better account for the undercoverage of maternal mortality common in most countries. New estimates for the adjusted are not yet available, and therefore this column has not been included.
Explanation of symbols
Since the aim of this statistics section is to provide a broad picture of the situation of children and women worldwide, detailed data qualifications and footnotes are seen as more appropriate for inclusion elsewhere. Only three symbols are used to classify the table data: