In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: Active vasculitis was noted in 36 . 3 % patients at baseline and 0 % at 3 years of follow - up .
### Output Text:
Active vasculitis was noted in 36 . 3 % patients at baseline and 0 % at 3 years of follow - up . 