Could you please help. I am having a hard time with this problem and I have to show all work.

In 1965, 42.4% of American adults described themselves as regular cigarette smokers. By 2005, only 22.4% of American adults described themselves as regular cigarette smokers. Use a linear equation that models this decline in smoking. Let x represent the number of years after 1965 and let y represent the percentage of American adults who described themselves as regular cigarette smokers.