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: There were 64 . 3 % Chinese , 31 % Malays , and 3 . 7 % Indians and other ethnic groups .
### Output Text:
There were 64 . 3 % Chinese , 31 % Malays , and 3 . 7 % Indians and other ethnic groups . 