Other websites will have on their Paypal donate page an option for monthly donations (and I’m not sure about yearly but that would also be a good idea).
This will better fund the project, rather than relying on people to remember to donate each year or every few months. We are all busy people and some of us more forgetful than others.
Just an idea / suggestion.
I am loving Ubuntu 18.04 btw, and I want this project to keep getting better and better. Cheers