Wow this is such a great question, I'd be happy to help!
We just finished up our unit on alchohol! Beer contains between four and seven percent of alchohol by volume! The average is around 5-5 1/2 percent by volume. It really just depends on the type of beer, the worlds strongest beer has something like 67 % of alchohol! But the average is around five percent.
Really hope this helps! Dont hesisate to ask any questions if your confused!!
:)