Yeah, its a combination of rolling and aero resistance. If you feel something is off you can check the air pressure in all 4 tires and go a step further by jacking up each corner and see if they rotate freely. If you arent into jacking your car another test is to feel how warm the wheels are after a drive. The warmer the wheel the more resistance is being generated by that part from a warn bearing to sticking or dragging brake pad or shoe.
Have you had a 4 wheel alignment in a while? If you tires wear funny, wear out faster than normal this can be another issue.