Whi is AIDS called an epidemic?

Epidemic refers to a disease going higher than projected outcomes within a population, so in the 80s they could say there was an AIDs epidemic in New York for example or California. A pandemic refers to a counrty or continent. So in the Africa there was an AIDs pandemic. Basically to have an epidemic, the disease has to be reported in higher numbers than what was projected for the certain period. Same for a pandemic but on a greater scale. So you could say ;last year there was an H1N1 pandemic in the US. but in California it was an epidemic. Get it?