Calculate the available real estate as a percentage:
EDIT:
This works but is not indicative of how the * parameter functions. This:
provides the same functionality. If you want something other than equal height rows you can use:
which will divide the available height by 10 and maintain the relative height of each row. Alternatively, the values could be 0.1, 0.2, 0.3, and 0.4 or any proportional value.
