4. Australia
3.36% of mass shootings
Luckily (well, considering the subject we have here), the most deaths by guns in Australia are suicides, and the most mass shootings that occur are within the family (committed by the father usually). Though after 1996, when Australia’s worst mass shooting occurred (involving 35 dead), gun control law was brought out which dropped the rate of mass shootings in Australia by 42% during the next seven years.