During the Reagan years, for instance, an average of 101 police officers were intentionally killed each year. Under George Bush snr that number fell to 90. It fell further, to 81 deaths per year, under Clinton, and to 72 deaths per year under George W. Bush.
Under Obama, the average number of police intentionally killed each year has fallen to its lowest level yet - an average of 62 deaths annually to the end of 2015. If you include the 2016 police officer shootings to date and project it out to a full year, that average of 62 deaths doesn't change.
It's worth pointing out that in 2016, year-to-date officer fatalities via shooting only are up 44 per cent over last year, according to the numbers compiled by the National Law Enforcement Officer's Memorial Fund. But that's partially an illustration of how sensitive these numbers are to individual incidents: if you set the Dallas shootings aside, the year-over-year increase is only 17 per cent. And as UCLA law professor Eugene Volokh points out, the 2016 numbers are roughly on par with the numbers for the past 10 years.
These figures include all incidents in which a suspect intended to kill a police officer - shootings, stabbings, assaults, bombings, and vehicular assaults. They exclude things like accidental shootings, job-related illnesses and traffic accidents. If you were to narrow it down to just shootings, the overall trend would be roughly the same: from 80 deaths annually under Reagan to 48 annually under Obama. Again, factoring in the 2016 shooting numbers, including Dallas, has a negligible effect on the average under Obama.
These falling fatality numbers aren't simply a function of better medical care for injured officers: overall assaults on officers are down too.
In 1988, the last year of the Reagan Administration, there were 15.9 assaults for every 100 sworn law enforcement officers according to the FBI.
In 2000, at the end of the Clinton Administration, there were 12.7 assaults for every 100 officers. By the end of the Bush Administration that number fell further to 11.3. Under Obama in 2014, the most recent year for which the FBI has data, that number further fell to 9.0.
One area where the numbers are a little murkier is ambush attacks like the Dallas shooting, where killing police officers is the sole intent of the crime. These are generally very rare, with the number of officers dying in these attacks each year in the single or double digits.
But they have become slightly more common: during George H.W. Bush's Administration (the first administration for which the FBI provides complete data) roughly eight officers died in ambush attacks each year. That rose to nine under Clinton, and 10 per year under George W. Bush and Obama (to the end of 2014).
The small numbers here make these attacks no less tragic - one dead police officer is too many, regardless of the cause. But they have to be understood in the context of a striking overall improvement in officer safety.
It's tempting to place credit or blame for these figures with whichever president happened to be in charge at the time, as many conservatives have done in recent days. But in reality police officer safety is much more closely connected to broader social trends than to who happens to be sitting in the White House.
Since the early 1990s, for instance, violent crime has plummeted. Motor vehicles have become much safer. States have passed laws making the roadways safer for police. All of these factors have contributed to the dramatic drop on police fatality rates, from all causes, that we've seen over the past few decades.
