This document is a technical report that presents findings on the calculation of total costs of ownership for personal motor insurance. It outlines the methodology used to determine the percentage cost of insurance for motor vehicles across various countries, utilizing consumer price index (CPI) data as a reliable basis for comparison. The report details the components considered in the total cost of ownership, including vehicle depreciation, fuel costs, insurance premiums, maintenance, and taxes. It also discusses the limitations of using CPI data, noting that definitions of insurance premiums may vary by country. The report proposes a global weighted average as an attribution factor for insurance costs and provides guidance on how insurance providers can calculate their own attribution factors based on the total cost of ownership approach. Additionally, it includes regional averages and specific country data for insurance costs, emphasizing the importance of accurate data sourcing.