Leading-edge hard disk drive areal densities from 1956 through 2009 compared to Moore's law
HDD areal density's long term exponential growth has been similar to a 41% per year Moore's law rate; the rate was 60–100% per year beginning in the early 1990s and continuing until about 2005,[41][42] an increase which Gordon Moore (1997) called "flabbergasting" and he speculated that HDDs had "moved at least as fast as the semiconductor complexity."[43] However, the rate decreased dramatically around 2006 and, during 2011–2014, growth was in the annual range of 5–10%.[44] Disk cost per byte improved nearly -45% per year during 1990–2010, and slowed after 2010 due to the Thailand floods and difficulty in migrating from perpendicular recording to newer technologies.[45][46][47] Moore (2005) further observed that growth cannot continue forever.[48]