You are given two tables for a voice-calling product: `users` - `user_id` BIGINT - `country_code` STRING `calls` - `call_id` BIGINT - `caller_id` BIGINT - `recipient_id` BIGINT - `started_at` TIMESTAMP `calls.caller_id` and `calls.recipient_id` both reference `users.user_id`. Assume: - Every row in `calls` is one valid call event. - All timestamps are stored in UTC. - Any date-based metric should be computed in the `Europe/London` timezone. - `report_date` is a calendar date in `Europe/London`. Write SQL to compute the following metrics for each `report_date`: 1. **Percentage of callers with at least 20 calls in the last 7 days** - Use the 7-day window ending on `report_date`, inclusive. - The numerator is the number of distinct users who initiated at least 20 calls in that 7-day window. - The denominator is the number of distinct users who initiated at least 1 call in that same 7-day window. 2. **Percentage of Great Britain DAU with at least 50 total calls** - Restrict to users with `country_code = 'GB'`. - Define daily active users as distinct GB users who either placed or received at least one call on `report_date`. - For each such user, count total call participations on `report_date`, where participations include both outgoing calls as `caller_id` and incoming calls as `recipient_id`. - The numerator is the number of GB DAU with at least 50 total call participations on `report_date`. - The denominator is all GB DAU on `report_date`. Return one row per `report_date` with these columns: - `report_date` - `pct_callers_20plus_last_7d` - `pct_gb_dau_50plus_calls`