diff --git a/include/armadillo_bits/constants.hpp b/include/armadillo_bits/constants.hpp
index de791d81..1d74eb9a 100644
--- a/include/armadillo_bits/constants.hpp
+++ b/include/armadillo_bits/constants.hpp
@@ -113,7 +113,7 @@ namespace priv
 
 
 //! various constants.
-//! Physical constants taken from NIST 2014 CODATA values, and some from WolframAlpha (values provided as of 2009-06-23)
+//! Physical constants taken from NIST 2018 CODATA values, and some from WolframAlpha (values provided as of 2009-06-23)
 //! http://physics.nist.gov/cuu/Constants
 //! http://www.wolframalpha.com
 //! See also http://en.wikipedia.org/wiki/Physical_constant