* National Centre for Social Research/national Foundation. Drug use, smoking and drinking among young people in England 2001: Preliminary results Department of Health. March 2006
**Using Government Office regions, SMRs are used to compare the regions taking account of any differences in the age and sex distribution of the population. The SMR ratio is the number of deaths actually observed, to the number of deaths expected if the region were like the country as a whole. This is expressed as a percentage, so the whole of the country would have an SMR of 100. Regions with an SMR greater than 100 have more deaths than would be expected is the country was uniform.