HELP- Extra Credit question

My sis has an extra credit question she needs help on. Typically how many tsunamis occur each year?

I tried researching but not coming up with anything

http://www.cbc.ca/news/background/forcesofnature/tsunamis.html


'How often do they occur?

There are an average of two tsunamis each year that cause damage somewhere in the world. About every 15 years, a destructive, Pacific-wide tsunami occurs, according to the U.S. government's West Coast and Alaska Tsunami Warning Center. '