What percentage of users were using Firefox according to the source that reported 15.40% used Safari?
CREATE TABLE table_name_66 (firefox VARCHAR, safari VARCHAR)
SELECT firefox FROM table_name_66 WHERE safari = "15.40%"
### Context: CREATE TABLE table_name_66 (firefox VARCHAR, safari VARCHAR) ### Question: What percentage of users were using Firefox according to the source that reported 15.40% used Safari? ### Answer: SELECT firefox FROM table_name_66 WHERE safari = "15.40%"