The biggest target takes the most hits

from here and here

Apparently Chrome has more than twice as many vulns this year as the next leading browser. I know more vulnerabilities doesn't necessarily mean Chrome is less secure than it's competitors. It has the most market share so it gets the most attention from people trying to find vulnerabilities. However, while that doesn't make it less secure, it does make it less safe. More attention from attackers (successful attention at that it appears) means that users of the software face more attacks than users of the alternative browser - and that has been the rationale behind using alternative software for a long time. If you're using something that has a smaller target on it's back, you're less likely to fall victim.