Your comment was about C# being "the best language in terms of features and improvements", nothing about usage numbers.
I agree that C# is far more widely used than Scala, but Scala is being used by significant numbers of developers esp. for Spark. Tiobe is also widely regarded as a pretty poor indicator of language adoption.
Scala is consistently #15 or #16 in various measurements. Just not in TIOBE as they decided to use the wrong search terms to look for, so TIOBE doesn't provide useful information in this case.
[0] http://www.tiobe.com/tiobe-index/