2006 Mazda 3 car vibrates at higher speeds

Hi, I have a question. My car slightly vibrates when car is travelling at speeds over 60 mph. It feels like the front end and steering wheel. Vibration disappears when car slows down or increases speed over 70 mph, sometimes the vibration is less at the same speed or more. What do you guys think causes this and how can I check it?

Thank you.