Complex sentence: However, Since UTF-32 uses 4 bytes for every character it is very space inefficient for most normal text in which non-bmp characters are so rare they may as well be considered non-existant for sizing discussions.
Split into simpler sentences: However, since UTF-32 uses 4 bytes for every character it is very space inefficient. Specifically, non-BMP characters are so rare in most text they may as well be considered non-existent for sizing discussions.