 Over two billion 8-bit microcontrollers were sold in 1997, and according to Semico, over four billion 8-bit microcontrollers were sold in 2006.More recently, Semico has claimed the MCU market grew 36.5% in 2010 and 12% in 2011.A typical home in a developed country is likely to have only four general-purpose microprocessors but around three dozen microcontrollers.