Since 1964, conclusive medical evidence of the deadly effects of tobacco consumption has led to a sharp decline in official support for producers and manufacturers of tobacco, although it contributes to the agricultural, fiscal, manufacturing, and exporting sectors of the economy. Policy and law restricting tobacco smoking has increased globally, but almost 6 trillion cigarettes are still produced each year, representing an increase of over 12% since the year 2000. Tobacco is often heavily taxed to gain revenues for governments and as an incentive for people not to smoke.