MODERN CIGARETTES = 10% ADDITIVES. “More additives have been introduced, and current cigarettes may contain up to 10 per cent additives by weight. Some of these additives may make addiction to tobacco as a source of nicotine more likely. They may affect addictiveness of the product or simply make smoking more attractive.”
http://ec.europa.eu/health/scientific_committees/opinions_layman/tobacco/en/