It appears I was mistaken above. The listing I provided above was just the mass murders committed with high capacity magazines.
"For much of the 20th century there were, on average, a handful of mass killings per decade. But that number spiked in 1980, and kept rising thereafter. In the United States, there have now been at least 62 mass shootings in the past three decades, with 24 in the last seven years alone."
Are Mass Shootings Becoming More Common in the United States? - Hit & Run : Reason.com
Now, let's see your documentation that shows either Norway or Finland had more that 24 mass shootings in the last 7 years?