It works on iOS, and I think there are a lot more iPhones out there than win7 desktops. ;)

Be that as it may, that doesn’t address the apparent fact that it doesn’t work in all major browsers — certainly IE11 would be considered one by most.

Moreover, whatever % of global browser share IE11 has, within the market of people who want charts, it's much higher. The simple chart is also the #1 feature priority of every business-IT product manager that has ever existed, narrowly beating "make it work in Internet Explorer".

Google Charts is a solid lib if you need the go-wide support