Io 0

Smalltalk 5

Lua 21

Python 28

C99 37

Ruby 40

Java 53

PHP 53

JavaScript 59

C++98 63

C# 77

Perl 180?

Note: Number of keywords obviously is not the only or particularly good measure of simplicity, but it is suggestive.
Recommendations for better measures of simplicity are welcome as long as they can be objectively measured.