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:
| Date | Name of ship | Flag | Tonnage | Fate |
| --- | --- | --- | --- | --- |
| 5December1944 | Proletarij | Soviet Union | 1123.0 | sunk at |
| 21December1944 | Reshitel'nyj | Soviet Union | 20.0 | sunk at |
| 26December1944 | RT-52 Som | Soviet Union | 417.0 | sunk at |
| 29December1944 | T-883 (No 37) | Soviet Union | 633.0 | sunk at |
| 2March1945 | BO-224 | Soviet Union | 105.0 | sunk at |
| 20March1945 | Horace Bushnell | United States | 7176.0 | damaged at |
Question:
What is the average tonnage of the ship named proletarij?
Answer:
1123.0