The AFQT score is a percentile ranking between 1 and 99 that shows where your score is placed in relation to others. For example, if you score a 54 on the AFQT, this means that you scored as well as or better than 54% of other recruits. If you are not satisfied with your score and wish to retake the test to improve your chances at getting selected, you must wait a month before taking it again. You can retake the test as many times as you want, but after 3 attempts the waiting period jumps to 6 months.
One ASVAB sub-measure, the Armed Forces Qualification Test (AFQT)--which is just a separate analysis of the same tests that focuses only on four of the subtests--is also population-referenced, but its score from 1-99 is a percentile score. This means that if you score a 73, you scored as well as or higher than 73% of test-takers in the national sample.