Who told you it is rare? We pretend too much, in America spiritualism and necromancy is common in fact there is a religion just for the same. The Chinese economy is booming but during their traditional religious festivals they will not even reply to an email for the entire season of up to one week, they will not ship your order until they finish their rituals. So they are not just common to Africans as many people want to believe, the truth is that they are not good practices.
In America spiritualism is institutionalised and comprises mostly middle and upper class according to a Wikipedia article.
Here is their website
nsac.org