superscripts 4, 5, 6, 7, 8, 9 not work in strings.xml

If I want to write into the file strings.xml the number one in the upper register (superscript), I use unicode symbol "\u00B9" and everything works fine. But if I want to write the numbers from 4 to 9 in the upper register, code "\u2074" - "\u2079" not work! How can I overcome this limitation without html and using only strings.xml?

thanks!