For most other languages the focus seems to be mainly on letters (typing out keywords/identifiers), so in that sense there is little evidence that one language would be easier to write than another.
Additionally, I imagine that some of the code is auto-completed by an IDE, which this analysis fails to account for.
As an aside, its interesting (to me, as a Colemak user) that all of the hot alphabetic characters in all the analyzed languages are on the home row of the Colemak layout (except L, which seems to be kind of hot in C++).
"Shouldn't shift be twice as hot as the parentheses?"
For offline analysis? No. Shift should be as hot as the SUM of both types of parentheses. In practice, both parentheses will be equal in count modulo some epsilon for unmatched parenthesis in strings and comments. Therefore, shift will be close to twice as either parenthesis.
For online analysis? No. Shifted characters can come into existence without being typed. For parenthesis, autocompletion is one way. Automatic bracket matching is another. There are many more, including template expansion, copy/paste, and several paredit operations.
Shift is used for many combinations besides just parentheses, such as that capital at the start of this sentence. It would likely be more than twice as much.
And furthermore, where are all the numbers, tabs and spaces?
~ $ curl -s 'http://lib.store.yahoo.net/lib/paulgraham/onlisp.lisp' | egrep -o '.' | sort | uniq -c | sort -nr
18641
3277 )
3276 (
2561 e
2159 a
1934 s
1903 r
1672 n
1661 t
1477 l
1380 o
1287 c
1282 d
1067 p
1064 i
1030 m
[...]
18641
3277 )
3276 (
1934 s
1903 r
1672 n
1661 t
1477 l
1287 c
1282 d
1067 p
1030 m
929 f
852 b
654 ,
601 g
[...]My first thought: 'unmatched paren?'
But I bet there's a smiley face on that page somewhere.
EDIT: If there is, I don't see it.
(let ((rpar (get-macro-character #\) )))
while the following do not: break, case, continue, default, double, else, enum, extern, register, return, signed, sizeof, typedef, unsigned, volatile