Rent rate for tenant

[Adam Azam]

I have great tenants in one of my properties that is reaching the end of the 2nd 2-year lease term. I did not bump rent when they renewed the lease so it will be 4 years without any increase. How much would you bump up the rent by? I think I should bump up the rent, but with all the uncertainties going on right now, I am trying to figure out what would be reasonable, but also fair for them.