The problem is the variety of factors which need to be controlled for in order to create a level playing field. Population density, average age, prevalence of preexisting conditions (esp. obesity), climate and volume of travel (both domestic and international) are just some of the factors which affect the threat posed by C-19. Without checking, I'm reasonably confident that areas like London and New York City, for instance, are at significantly greater risk than Melbourne (largest city in Victoria) according to those variables.