The StackOverflow survey has C++ used by over 20% of respondents, with just of over 50% wanting to still use it next year:
https://stackoverflow.com/insights/survey/2017/
This isn't exactly what you are looking for, but I think it still shows that C++ is fairly popular. C is second among systems languages at 19% and Go is near 4% (Rust is presumably less than 1.8% since it's not even on the list)