Arguably, the greatest invention that affected not just the military, but all society, after adoption of fire, was the wheel, and its use in the construction of the chariot. There were no advances in military technology, until, from the mechanical arm action of a slinger, the Greeks, Egyptians, Romans, Persians, Chinese, etc., development the siege engines. The bow was manufactured in increasingly larger and more powerful versions, to increase both the weapon range, and armour penetration performance. These developed into the powerful composite and recurve bows, and crossbows of Ancient China. These proved particularly useful during the rise of cavalry, as horsemen encased in ever-more sophisticated armour came to dominate the battlefield.
The percentages of FY 1999 active duty NPS accessions in each AFQT category are shown in Table 2.8. The percentage of recruits in Categories I and II was approximately the same as their civilian counterparts (males - 39 versus 39 percent; females - 34 versus 33 percent). Category III accessions greatly exceeded civilian proportions (males - 61 versus 30 percent; females - 66 versus 37 percent), while the percentage of recruits in Category IV was much lower than in the civilian population (males - 1 percent versus 20 percent; females - less than 1 percent versus 22 percent). The low percentage of Category IV recruits is, in part, a result of DoD limits of 4 percent Category IV recruits, with even lower Service limits. Ten percent of civilian males and 9 percent of civilian females scored in Category V; DoD allows no Category V recruits.
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.