One way is to have a counter variable to increment count of the index of the largest number when it is found again, else reset to 1 if a new largest number is found. Partial pseudo code look like this:
INITIALIZE largestCount = 0
Inside the loop to locate the next largest number:
if numbersList[ index ] == numbersList[ largest ]:
largestCount += 1
# other code
elif numbersList[ index ] > numbersList[ largest ]:
largestCount = 1
# other code