Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
|  | Delivery in Calendar Years Ending | Delivery in Calendar Years Ending | Delivery in Calendar Years Ending | Delivery in Calendar Years Ending | Delivery in Calendar Years Ending |
| --- | --- | --- | --- | --- | --- |
|  | 2019 | 2020 | 2021 | After 2021 | Total |
| A220-100 | 24 | 12 | — | — | 36 |
| A220-300 | — | 6 | 12 | 32 | 50 |
| A321-200 | 32 | 27 | 3 | — | 62 |
| A321-200neo | — | 16 | 36 | 48 | 100 |
| A330-900neo | 4 | 4 | 9 | 18 | 35 |
| A350-900 | 2 | 2 | — | 10 | 14 |
| B-737-900ER | 18 | — | — | — | 18 |
| CRJ-900 | 7 | 8 | — | — | 15 |
| Total | 87 | 75 | 60 | 108 | 330 |
Question:
What is the total number of aircraft on Delta airlines' purchase commitments as of the end of 2018? 
Answer:
330