In FORMAT chapter this example
(format t " Percentages are ~,,2f percent better than fractions" .77)
with expected output:
Percentages are 0.77 percent better than fractions
works in abcl clisp sbcl cmucl
But does not work that way in clozure cl, ecl, allegro-express:
Percentages are 0.77 percent better than fractions
For some details look here
http://trac.clozure.com/ccl/ticket/835