Unless you enjoy the amount of spam that is being, forcibly posted onto your WordPress Blog, don't show off your Akismet stats!
Why not? Because Spammers use the counter to test their WordPress Spamming software. If they see the counter increase, they know they Spam has been caught. If they don't see the counter and they see that their spam is not posted, they begin to think sending Spam to your site is not helping them.
Spammers are constantly trying to compromise Akismet. You don't want Spammers to use your site to compromise Akismet, do you? Then, don't reveal your Akismet stats on your website.