Count complaints, optionally grouped. group_by is one or two of: year, quarter, month, product, sub_product, issue, sub_issue, company, state, company_response, company_public_response, submitted_via, timely_response. Returns complaints, timely_rate, monetary_relief_rate, nonmonetary_relief_rate, in_progress_rate per group (rates are fractions of that group's complaints). Counts are raw complaint counts, not adjusted for company size. In progress and Untimely response are CFPB response categories, not outcomes. Filters: company (exact name as in find_company), company_contains (substring), product, sub_product, issue, product: CFPB renamed credit reporting twice, so it appears under three product names (use list_values field=product), company_response (exact CFPB value, case-insensitive), submitted_via, state (2 letters), tag (e.g. 'Servicemember', 'Older American'), timely (true/false), date_from/date_to (YYYY-MM-DD or YYYY-MM, on date received).