percentage of weekly visits to emergency departments for illness and injury by patients arriving via ambulance, by day night period of arrival united states, 2003 2004 /

Percentages indicate the proportion of weekly visits for illness or injury distributed over 14 periods (day and night). Overall,persons who arrive by ambulance at an emergency department (ED) are more likely to effect so because of illness (57%) than injury (43%). However, on Saturdays, or ambulances are more likely to bring persons with injuries than illnesses,both during the day and at night. Ambulance-transported patients account for approximately 15% of all ED visits and 16 million patients annually.

Source: cdc.gov