The percentage p-character in $s{p}^3$ hybridization is ______.

One s orbital and three $p$ orbitals combine to form four sp3 orbitals, each of which contains 25% s character and 75%  $p$ character. This process is known as $s{p}^3$ hybridization. Anytime an atom is surrounded by four groups of electrons, this kind of hybridization is necessary.