EMS is sometimes provided by volunteers. Agencies that were once strictly volunteer have begun supplementing their ranks with compensated members in order to keep up with booming call volumes. As of 2004, the largest "Private Enterprise" provider of contract EMS services in North America was American Medical Response, based in Greenwood Village, Colorado. The second-largest US EMS provider is Rural/Metro Corporation, based in Scottsdale, Arizona; Rural/Metro Corporation also provides EMS services to parts of Latin America. Like AMR, Rural/Metro provided other transportation services, such as non-emergency transport and "coach", or wheelchair, transportation. On October 28, 2015, AMR announced that it had finalized the acquisition of Rural/Metro, forming the largest EMS organization in the United States and employing nearly 25,000 individuals.