May be you get some idea from this:
Pattern  : ^\d{1,2}\.\d{1,2}$|^\d{1,2}$
Match 1
Full match  0-4 0.01
Match 2
Full match  5-10    99.99
Match 3
Full match  11-16   01.01
5
solved Regular expression Range with decimal 0.10 – 99.99
 
May be you get some idea from this:
Pattern  : ^\d{1,2}\.\d{1,2}$|^\d{1,2}$
Match 1
Full match  0-4 0.01
Match 2
Full match  5-10    99.99
Match 3
Full match  11-16   01.01
5
solved Regular expression Range with decimal 0.10 – 99.99