What is the ratio of the incidence of schizophrenia in members of lower socioeconomic groups compared to higher socioeconomic groups?

Some studies have found that there is a higher risk for later schizophrenia to develop for children who belong to higher social classes compared to middle and working classes. In the lower classes, schizophrenia has only been recorded in the very lowest social class or to those whose parents face adversity such as unemployment, disability, etc.