what percent of american's total planes carried fewer than 100 pasengers?
item 2 . properties flight equipment and fleet renewal as of december 31 , 2017 , american operated a mainline fleet of 948 aircraft . in 2017 , we continued our extensive fleet renewal program , which has provided us with the youngest fleet of the major u.s . network carriers . during 2017 , american took delivery of 57 new mainline aircraft and retired 39 mainline aircraft . we are supported by our wholly-owned and third-party regional carriers that fly under capacity purchase agreements operating as american eagle . as of december 31 , 2017 , american eagle operated 597 regional aircraft . during 2017 , we reduced our regional fleet by a net of nine aircraft , including the addition of 63 regional aircraft and retirement of 72 regional aircraft . mainline as of december 31 , 2017 , american 2019s mainline fleet consisted of the following aircraft : average seating capacity average ( years ) owned leased total .

|  | Average SeatingCapacity | AverageAge(Years) | Owned | Leased | Total |
| :--- | :--- | :--- | :--- | :--- | :--- |
| Airbus A319 | 128 | 13.8 | 21 | 104 | 125 |
| Airbus A320 | 150 | 16.7 | 10 | 38 | 48 |
| Airbus A321 | 178 | 5.4 | 165 | 54 | 219 |
| Airbus A330-200 | 251 | 6.0 | 15 | — | 15 |
| Airbus A330-300 | 291 | 17.4 | 4 | 5 | 9 |
| Boeing 737-800 | 160 | 8.1 | 132 | 172 | 304 |
| Boeing 737-8 MAX | 172 | 0.1 | 4 | — | 4 |
| Boeing 757-200 | 180 | 18.1 | 31 | 3 | 34 |
| Boeing 767-300ER | 209 | 19.1 | 24 | — | 24 |
| Boeing 777-200ER | 269 | 17.0 | 44 | 3 | 47 |
| Boeing 777-300ER | 310 | 3.8 | 18 | 2 | 20 |
| Boeing 787-8 | 226 | 2.1 | 20 | — | 20 |
| Boeing 787-9 | 285 | 0.7 | 14 | — | 14 |
| Embraer 190 | 99 | 10.2 | 20 | — | 20 |
| McDonnell Douglas MD-80 | 140 | 21.3 | 13 | 32 | 45 |
| Total |  | 10.1 | 535 | 413 | 948 |

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planes_fewer_than_100 = 20
planes_total = 948
percent_fewer_than_100 = planes_fewer_than_100 / planes_total
answer = percent_fewer_than_100 * 100