BOSTON, Aug. 30 - The level of nicotine that smokers typically consume per cigarette has risen 10 percent in the past six years, making it harder to quit and easier to be addicted, said a report that the Massachusetts Department of Health released on Tuesday.

The study shows a steady increase in the amount of nicotine delivered to the smokers' lungs regardless of brand, with overall yields increasing 10 percent.

Massachusetts is one of three states to require tobacco companies to submit information on nicotine testing to its specifications and is the sole state with data as far back as 1998.

The study found that the three most popular brands with young smokers, Marlboro, Newport and Camel, delivered significantly more nicotine than they did six years ago. Nicotine consumed in Kool, a popular menthol brand, rose 20 percent.