PostgreSQL Index hit percentage by table

gistfile1.sql

SELECT
  schemaname::text,
  relname::text, 
  seq_tup_read,
  idx_tup_fetch,
  seq_tup_read + idx_tup_fetch as total_reads,
  round(100 * idx_tup_fetch / (seq_tup_read + idx_tup_fetch)) as idx_read_pct,
  pg_size_pretty(pg_total_relation_size(relid)) as total_size
FROM  
  pg_stat_user_tables
JOIN   
  pg_stat_database ON datname = current_database()
WHERE
  (seq_tup_read + idx_tup_fetch > 0) AND   
  tup_returned > 0
ORDER BY  
  (seq_tup_read + idx_tup_fetch) desc -- A.K.A. "total_reads" 
limit 
  50;