It all varies so much. You need to take into consideration what weighs what. I am sure it is posted on here somewhere- one of the Mods should know.

But it can all depend on if you had m/s and gained little or no weight at the start of pg (or like me ate constantly), fluid retention, placenta and babies weight, amniotic fluid, bb's weight/size change, the size of bubs, your body structure and metabolism, etc.....

I wouldn't be too concerned with weight gain as long as bubs is growing well and you are healthy.