Update README.md

README.md

@@ -35,7 +35,7 @@ Just copy the files to your build tree and use a C++11 compiler
 
 ## Benchmarks
 
-Here are some [benchmarks](bench) comparing spdlog vs other libs <sub>(Ubuntu 64, Intel i7-4770 CPU @ 3.40GHz)</sub>.
+Here are some [benchmarks](bench) comparing spdlog vs other libs <sup>(Ubuntu 64, Intel i7-4770 CPU @ 3.40GHz)</sup>.
 
 The bench writes 1,000,000 log lines to a rotating log file (using shared synchronous logger object):