Fourteen years of accident data from the International Helicopter Safety Team (IHST) reveal that U.S. civil helicopter accidents have decreased by approximately 25 percent since the IHST was established in 2006, with an average annual drop in accidents of around 2 percent.

Between 2000 and 2005 the U.S. averaged 188 helicopter accidents annually. That number declined to 170 during 2006-2007, to 156 during 2008-2009 and to about 140 annual accidents between 2010 and 2013. However, total U.S. accidents crept up to 148 in 2012 and 147 last year.

The United States Helicopter Safety Team released a comprehensive report last week comparing U.S. civil helicopter accidents in 2009, 2010 and 2011 with those that occurred in 2000, 2001 and 2006 to pinpoint where improvements or regression have occurred. During the 2009-11 period there were 415 civil helicopter accidents, a 21-percent reduction compared to the total 523 accidents that occurred during 2000, 2001 and 2006, years the agency used to establish a baseline.

The rotorcraft sectors showing the greatest safety improvements were firefighting (down by 2.6 percentage points of total accidents), air tours (down 2.3 points), logging (down 2.2 points) and news/traffic helicopter operations (down 1.5 points).

Nearly half of all U.S. civil helicopter accidents involved agricultural aerial applications, personal flying and flight instruction. Agricultural accidents as a percentage of the total increased by 5.4 points, while personal flying rose by 2.2 points and instructional activity climbed 2.9 points.