What is the actual risk of heart attack?

What is the risk percentage figure that people base all the other percentages on such as smoking doubles the risk or eating barbecued meat increases your chance of heart attack by 15%. 15% of what figure?

The same goes for stroke or any of those other diseases where you hear stories that if you do this or that then your risk is increased of getting it. Whats the actual (or base figure) risk so that I can analyse better what the chances really are of getting one of these things.

So say the actual risk of heart attack is 1% and then if I smoke that doubles the risk of me having a heart attack to 2%. Then I can decide from there whether it is worth the risk to keep smoking. OK smoking may not be a good example to use because we all know it's bad for us but you get the idea.