Certain letters are coded as : TODAY-457338 WROTE-10542. DATE-7342 and DIRTH-79046. What does the code number '5' stand for ?

The manner of coding is

$\begin{array}{l}\text{ TODAY }\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}\text{WROTE }\hspace{0.25em}\hspace{0.25em} \hspace{0.25em} \hspace{0.25em} \text{DATE }\hspace{0.25em} \hspace{0.25em}\hspace{0.25em}\hspace{0.25em}\text{DIRTH }\\ 45738\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}\hspace{0.25em} 10542 7342\hspace{0.25em}\hspace{0.25em} 79046\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}\end{array}$

The number '5' is common in words TODAY and WROTE, and so is the letter 'O'. Letter 'T' cannot be the answer because it is common in all the four words and so is its number code '4'.