The development and introduction of MR heads in 1991, GMR heads in 1997, and AFC pixie dust media in 2001 (see the next section) subsequently drove a further increase in the areal density growth rate to 100% annually. The result of all this growth in density is amazing. In just slightly more than 50 years since the RAMAC drive was introduced, the areal density of magnetic storage has increased more than 200 million fold, from 2Kb/sq. inch in the 1956 RAMAC (5MB of storage on fifty 24-inch platters) to beyond 500Gb/sq. inch in 3TB drives in 2010.