Number of Conflict years

Hello Everyone,

I have a dataset that looks like this :

ConflictId Location endyear startyear yrs
1-10 Philippines 1946 1946 0

It describes the conflict events that a country faces. For each observation I have the conflict starting year, end year and duration of the conflict. I want a variable that calculates the number of conflict years that a country faced in the past five years. Any help with that ?!

Thanks