That's still much, much higher usage than jsvu[1] which they gave as the justification for needing this polyfill. 0.35% of Internet users is ~14 million people. jsvu has been on npm for about a year and has never had more than 1000 downloads per week, so it has under 50k users, more than two orders of magnitude less than IE<11.
[1] https://www.npmjs.com/package/jsvu