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: The incidence rate of thromboembolism was 0 . 9 % for all the studies and 0 . 5 , 0 , 20 , and 0 % in groups a , b , c , and d , respectively ; for hemorrhage , the overall rate was 3 . 4 % ( 3 . 8 , 2 . 6 , 10 , and 0 % for the respective groups ) .
### Output Text:
The incidence rate of thromboembolism was 0 . 9 % for all the studies and 0 . 5 , 0 , 20 , and 0 % in groups a , b , c , and d , respectively ; for hemorrhage , the overall rate was 3 . 4 % ( 3 . 8 , 2 . 6 , 10 , and 0 % for the respective groups ) . 