How many people do voodoo?

Voodoo is praticed by millions every where in the world. Specially in Haiti(the country where it is mostly practiced), Cuba, the Dominican Republic, Canada, the United States(specially in Louisianna and where there's a considerant population of Haitian Immigrants), many country in Africa etc... it is quite impossible to know exactly how many people practice it. but one thing for is sure, it is practices by millions all over the world.