Portable wireless speakers are becoming increasingly popular, due to the diffusion of handheld media devices. These products are sold online and through electronics retailers.
There are numerous competitors, including Jawbone, Audiovox, Sony, Spracht, Philips and Uniden. Product examples include the Spracht Aura Blu Note ($49 - $79) and the Bose Soundlink ($299).
U.S. national sales of portable wireless speakers were $ 92.8 million for 2010 (the latest year for which data are available). Of this amount, the 24 to 40 year old segment accounted for $ 30.9 million. This segment makes up 21 % of the U.S. population (currently estimated at [309] million individuals.
Calculate the category development index (24 to 40 year olds) for portable wireless speakers. Report your answer to two decimal places.