DHB service. Land ambulance St. John provides service to approximately 88 percent of the population of New Zealand and 17 district health boards (DHBs), through a network of 553 ambulances and 183 ambulance stations. St. John Ambulance reports the completion of approximately 274,108 emergency responses for the year ending 1 July 2008. By contrast, Wellington Free Ambulance provides service to 12 percent of the population of New Zealand and three district health boards (Capital & Coast, Hutt Valley and Wairarapa), providing service to more than 500,000 residents. They respond to an estimated 40,000 calls per year. Air ambulance Air ambulance and helicopter rescue services are vital given the low population density of New Zealand and the significant distances between tertiary hospitals. There are a large number of operators with all being sponsored by a commercial entity and bearing its name for marketing purposes; for example Auckland, Waikato and Wellington helicopters are sponsored by the Westpac Banking Corporation and branded as "Westpac Rescue" while others include the Taranaki Energy Rescue Helicopter, Square Trust Rescue Helicopter, Bay Trust Rescue Helicopter etc. Clinical crew (typically Intensive Care Paramedics) for the helicopters are full time employed Intensive Care Paramedics. Domestic fixed wing air ambulance services are typically use pressurised and converted Fairchild Metro aircraft, equipped as flying Intensive Care units. and it has been estimated that after corporate sponsorship and government subsidy, it is necessary to raise approximately NZ$2,500 (around US$1,400 in 2009) in donations for each mission. Fire and Emergency New Zealand Fire and Emergency New Zealand (FENZ) provides a medical 'First Response' in smaller communities where there is no local Ambulance service. These fire personnel are trained to a higher standard than regular firefighters and are equipped with basic ambulance equipment. As of Christmas 2013, FENZ 'Co- Responds' to all "Code Purple" (typically cardiac or respiratory arrest) emergencies St John Ambulance and Wellington Free Ambulance attends nationwide. The standard FENZ response to a medical emergency is one Fire Appliance equipped with an automated external defibrillator and oxygen therapy kit. Military The New Zealand Defence Force has personnel and equipment available at short notice to assist in civilian matters including medical emergencies. Models of care The New Zealand system functions on the Anglo-American model of care, with most care in the pre-hospital setting being conducted by paramedics. Other practitioners, including local physicians and midwives, do appear at calls from time to time, but