Police Deaths Decline

Today the newspaper printed some interesting statistics. During  President Reagan's eight years in office about 90 to 100 police officers were killed each year, and during Obama's two terms about 60 officers a year have been killed. I don't have the facts, but I am fairly sure that countries like Japan, Great Britain, France and Germany lose a few officers each year and in good years lose no one. I don't believe that reducing the number of American officers killed by 30% is good enough, but obviously we have been doing something better. What is it? Why has the number declined that much?  What can we learn from this?  Why aren't our leaders talking about it?