After adding so much information to the aptitude test, there was a bit of difficulty interpreting the test results. In addition to that, a vast majority of test takers were deemed as being under qualified based on their test results. This is why the percentile change was made. It ensured that a 50% actually correlated with a person doing better than 50% of the test takers. Those revisions have worked hand-in-hand with the preparation of the armed forces.
AFQT scores are reported as percentiles between 1-99. An AFQT percentile score indicates the percentage of examinees in a reference group that scored at or below that particular score. For current AFQT scores, the reference group is a sample of 18 to 23 year old youth who took the ASVAB as part of a national study conducted in 1997. Thus, an AFQT score of 95 indicates that the examinee scored as well as or better than 95% of the nationally-representative sample of 18 to 23 year olds. An AFQT score of 60 indicates that the examinee scored as well as or better than 60% of the nationally-representative sample.
The scores from the other tests are used to determine what type of specialty you might be best suited for.  These "composite" scores (also known as line scores, MOS scores, or aptitude area scores) are calculated by adding together combinations of the different sub test standard scores. These composite scores are then used to determine which different military jobs (aka Military Occupational Specialties or MOS) may be the best fit for you.  Each branch of the military will have their own approach to these composite scores.
The questions that have a tendency to arise rather quickly are something along the lines of “why is this test so important?” and “What is the overall purpose of this test?” Well, first it is important to define the actual test and to assess the colorful history of the test. The Armed Services Vocational Aptitude Battery test (ASVAB) is a test that was officially formatted in 1968 with the intention of mentally preparing soldiers with knowledge that identifies with the following: