[User Story] As a product team, we want know how many users customize their startup experience [Acceptance Criteria] Out of all the users who use "Preferences" in a month, 1. We know how many users set home pages 2. Out of all the users who set home pages, we know how many users set more than one home pages 3. Out of all the users who set home pages, we know how many users set home pages by using "Use Current Pages" and "Use Bookmark". 4. We know the proportion of choosing each of the items in the dropdown menu of "when Firefox starts".