SELECT rank FROM captain GROUP BY rank ORDER BY count(*) DESC LIMIT 1
SELECT rank FROM captain GROUP BY rank ORDER BY count(*) DESC LIMIT 1 <table_name> : captain col : Captain_ID | Name | Ship_ID | age | Class | Rank row 1 : 1 | Captain Sir Henry Langford | 1 | 40 | Third-rate ship of the line | Midshipman row 2 : 2 | Captain Beves Conway | 2 | 54 | Third-rate ship of the line | Midshipman row 3 : 3 | Lieutenant Hugh Bolitho | 3 | 43 | Cutter | Midshipman row 4 : 4 | Lieutenant Montagu Verling | 4 | 45 | Armed schooner | Midshipman row 5 : 5 | Captain Henry Dumaresq | 5 | 38 | Frigate | Lieutenant row 6 : 6 | Captain Gilbert Pears | 2 | 60 | Third-rate ship of the line | Lieutenant row 7 : 7 | Commander Richard Bolitho | 3 | 38 | Sloop-of-war | Commander, junior captain
col : Rank row 1 : Midshipman