Not sure what to make of this

This has been bugging me for some time, and I'm not sure if I should be worried (that I have a problem) or happy (that I don't) as I'm not sure what to make of this.

 

When I look at the Firewall logs for vulnerability protection it appears that only 1 ISP was consistently blocked.  It stopped recording blocks as of  Oct 16, 2011.  There have been no vulnerability blocks recorded since then.  Am I protected or not? 

 

I am running  OS X version 10.5.8, Safari 5.0.6 and NIS version 2.2 (5), I'm sorry if this doesn't make a lot of sense, but I'm new to this and not very computer savy.  Thanks for your help.