Age and vehicle factor most likely. Look at it like this: Like a typical electric bill, you get a base charge, whether you use any electricity or not. But any variance to the base, they charge you more. Car insurance is similar. Mustang and Camaro are not going to be cheap out of the box depending on your age. But if you have ticket or in an area that has a higher accident rate, etc., you'll pay more.
2010 2SS/RS Auto, Sunroof, Engine Cover. Transformer Edition package.
2013 ZL1 ragtop #5478. 1 of 54 CRT M6 'verts.