Postgresql
\n\n# Code\n\n-- Write your PostgreSQL query statement below\n\n\nSELECT\n    ROUND(COUNT(player_id)::NUMERIC / (SELECT COUNT(DISTINCT player_id) FROM Activity)
\n\n# Code\n```\n-- Write your PostgreSQL query statement below\n\n\nSELECT\n    ROUND(COUNT(player_id)::NUMERIC / (SELECT COUNT(DISTINCT player_id) FROM Activity) ::NUMERIC ,2)AS fraction\nFROM\n    Activity\nWHERE\n    (player_id, event_date - 1) IN (SELECT player_id, MIN(event_date) FROM Activity GROUP BY player_id)\n\n\n```
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