Region of eastern england has what investment income?
CREATE TABLE "sources_of_income" (
  "region" text,
  "employment_salaries_wages" text,
  "self_employed" text,
  "investment_income" text,
  "working_tax_credit" text,
  "state_pensions" text,
  "occupational_pensions" text,
  "disability_benefits" text,
  "other_social_security_benefits" text,
  "other_income_sources" text
);
SELECT "investment_income" FROM "sources_of_income" WHERE "region"='eastern england';