What is the dilution factor in this case?

Procedure:
1. pipette 25ml of calcium gluconate injection solution and 5ml of standard MgSO4 (0.05M) solution into a conical flask, add 1/4 small spatula spoon of eriochrome black T indicator and 10 ml of the ammonia buffer, which is provided in a dispenser.

2. Record the initial volume of disodium edetate solution before titragluconate and MgSO4 mixture until the end point colour change is observed. Record final volume of disodium edetate solution.

3. Repeat titration two times and calculate the average molarity of the calcium gluconate injection solution.

the 3 titrations:
V2-V1 (ml):
16
21.2
25.5

The question asks:
Calculate the percentage (weight/volume) of CALCIUM in the calcium gluconate injection solution.  Note: calcium gluconate injection solution used for titration has been diluted.  Record dilution factor and adjust your calculations accordingly.