15 March 2017 Last updated at 22:08 GMT
With the explosion of social networking that figure could increase, but is it something students and schools are well enough prepared for?
School reporters at St Patrick's College in Maghera have been investigating.
This report was originally broadcast as part of BBC News School Report.
You can find more School Report stories produced by young people in Northern Ireland here.
Figures released by the NSPCC in November showed that online or cyber bullying had increased by 88% in the last five years.