The Dallas ambush is an outlier in an unprecedented era of safety for cops

The ambush on a Black Lives Matter protest in Dallas on Thursday that left five police officers dead and seven others injured was the deadliest incident for law enforcement officials in America since September 11, 2001, when 72 officers were killed.

But the number of officers shot and killed on duty has been on a steady decline since the 1970s, making this the safest decade in American history to be a police officer. An average of 127 officers were fatally shot each year in the 1970s, compared to 53 per year thus far in the 2010s, according to the National Law Enforcement Officers Memorial Fund, which track police deaths in the line of duty.

The number of on-duty officer deaths overall — including those caused by vehicle accidents, health conditions and other factors — is also lower than ever. The 1920s were the most dangerous time to be a police officer, with approximately 243 officer deaths each year. In the 2010s thus far, there has been an average of 149 overall deaths each year.

In 1930, 193 officers were shot and killed in the US, the highest number of death by gunfire since the first recorded police death in 1791. In 2015, 42 officers were shot and killed.

Yet Steven Weiss, the director of research at Officer Down Memorial Page, says these statistics may not mean it has become safer to be a police officer.

"The numbers can be deceiving. It may lend you to believe that it's much safer to be a police officer because there's much less police officers being killed. But that doesn't necessarily mean the attempts to injure them aren't there," he explained.

Weiss said that improved medical technology and equipment for police officers are partly responsible for the decline in police deaths.

"There was almost nobody wearing bullet resistant vests [in the 1970s]," Weiss said, "so if you got shot in the chest in [the 1970s] as a police officer on patrol, there was a good chance you were going to die." Weiss said officers now have a significantly better chance of surviving these incidents.

Weiss also said police officers now receive more information before responding to calls, allowing them to be more adequately prepared for potentially dangerous situations.

Weiss noted that his organization does not collect data on the number of incidents where police have been attacked, so he is unable to provide empirical evidence to counter the idea that it has become safer to be a police officer.

Loggers, roofers, farmers, and taxi drivers are all more likely to die on the job than police officers, according to the Bureau of Labor Statistics' 2014 Census of Fatal Occupation Injuries.

The census found that loggers have the most dangerous job in America, suffering almost 111 fatal injuries per 100,000 people in 2014, compared to 13.5 for police officers, who placed fifteenth on the list.

Last night's protest in Dallas was one of many held across the country in response to police killing eight people between July 5 and 6, including Philando Castile, whose final moments were broadcast on Facebook by his girlfriend after a police officer opened fire during a traffic stop, and Alton Sterling, shot several times while being pinned down by two police officers.

The officers involved in the Sterling shooting told police investigators looking into the case that they believed their actions were justified, according to the East Baton Rouge Parish District Attorney, Hillar Moore. Recent investigations into alleged police misconduct, including the shooting of Michael Brown and the choking death of Eric Garner, failed to indict the responsible officers, ruling that their actions were self defense.

A database of police killings compiled by the Guardian, shows that at least 566 people have been shot and killed by police in the US this year.

Follow Davide Mastracci on Twitter: @DavideMastracci