The fraction is 2/3
So, there should be 100 squares.
Next, the 100 squares is divided into 3 by vertical lines. The lines will not coincide with the sides of the squares. This is okay. Next, the 2 out of 3 will be shaded, this will be equivalent to 66 squares and one more square but it will not be filled up completely. In percent form, the fraction is 66.67%.