Smokers have yet another incentive to give up the habit - prices have just gone up again. Philip Morris has put the price of Marlboro up by ten pesetas a packet, while its other popular brands, Chesterfield and L&M have gone up by 15 pesetas. A pack of 20 Marlboros now costs 385 pesetas and Chesterfields cost 325 pesetas. Various surveys conducted among Spanish smokers produced two obvious trains of thought, though: one, that the price increase would make them start thinking about giving up and the other, that it would make absolutely no difference at all. The latest price increase comes shortly after the World Bank and the World Health Organisation (WHO) called on developing countries to raise the price of cigarettes to encourage people to stop smoking and prevent millions of tobacco-related deaths. They advised raising taxes to dissuade consumers, which would hit the tobacco industry ha