The primary driver for Bluetooth handsets is the desire to connect to Bluetooth mono headsets, nearly 33 mln of which shipped in 2005, InStat reports. This figure is expected to increase to over 55 mln in 2006. GSM phones have adopted Bluetooth most rapidly, with one-third of GSM handsets in 2005 shipping with Bluetooth. European and Japanese automakers made Bluetooth capability available in a greater variety of higher-end cars in 2005. 50% of average US consumers claimed to be “Extremely Familiar” with Bluetooth technology, compared to a mere 2% of respondents in a 2005 survey.