Thunderbird security measured up against other clients

I was browsing around Wikipedia when I chanced upon this in the Mozilla Thunderbird article:

As of March 14, 2005, security site Secunia counts 1 unpatched security flaws not yet fixed for Mozilla Thunderbird 1.x, compared to 6 unpatched security flaws for Microsoft Outlook Express 6, 2 unpatched security flaws for Eudora 6.x and 0 unpatched security flaws for Ximian Evolution 1.4.x.

Is Thunderbird safe enough for general purpose use, especially in corporations? You be the judge.