sentences:  While digital storage has become cheaper, the associated costs, from raw power to maintenance and from metadata to search engines, have not kept up with the proliferation of data.Although the power required to maintain a unit of data has fallen, the cost of facilities which house the digital storage has tended to rise.Data proliferation has been documented as a problem for the U.S. military since August 1971, in particular regarding the excessive documentation submitted during the acquisition of major weapon systems.