Percentage of Box Filled In

Create a function that calculates what percentage of the box is filled in. Give your answer as a string percentage rounded to the nearest integer.

Examples

percentFilled([
  "####",
  "#  #",
  "#o #",
  "####"
]) ➞ "25%"

// One element out of four spaces.

percentFilled([
  "#######",
  "#o oo #",
  "#######"
]) ➞ "60%"

// Three elements out of five spaces.

percentFilled([
  "######",
  "#ooo #",
  "#oo  #",
  "#    #",
  "#    #",
  "######"
]) ➞ "31%"

// Five elements out of sixteen spaces.

Notes

• Only "o" will fill the box and also "o" will not be found outside of the box.
• Don't focus on how much physical space an element takes up, pretend that each element occupies one whole unit (which you can judge according to the number of "#" on the sides).