The entire suite of 1,000 official NOAA nautical charts has been available in digital raster form since 1995. These high quality, full color, geo-referenced images of NOAA's paper charts are made for use in computer-based navigation systems and work with GPS or other electronic positioning systems. They are produced jointly by NOAA and Maptech, Inc. under a cooperative research and development agreement (CRADA). Mariners quickly adopted raster nautical charts. Their rapid adoption was aided by first-rate navigation software available from many companies at an affordable price. Today, the raster charts outsell NOAA's paper charts by eight to five.