When I lived in Canada, I tried to donate often. During my thirteen years in Korea, my rate dropped as it was too much effort to break the language barrier. See here (for Busan) and here (Gangneung in Gangwondo) for those stories.
This will likely be my only donation this year, which is pretty weak. My grandfather donated around 100 times and that was back when you could only donate two or three times a year. The clinic was at the Best Western at King St and Highway 12.