I have just started a business blog... is there somewhere that I could find stats
about the percentage of success with SEO loaded blogs vs. just regular articles
with fresh content added often?

I don't know about actual stats, but I do know there are a lot of opinions out there on this topic. The prevailing opinion, at least in terms of my own research, is that "regular" fresh content is the way to go. Yes, you will be wise to add some keywords, but still, the best blogs have meaningful, fresh content. It will take longer for the audience to build, but you will build a loyal readership this way.

Hi.

I agree... the best way to go with blogs is to publish real content
that is geared for human readers. And to publish it frequently.

Of course, you may still do some SEO for the blog and optimize
each post's title tag, meta tags, etc... but the blogosphere is not
forgiving when it comes to spammy-looking blogs, so look out
for that and give your audience what they really want: fresh
and relevant information on the subjects you're talking about.

All the best!
Miguel Alvarez
Copywriting.com

just make sure that you do the standard filling of the metatag like title, description and keywords.
If its done right google will not only not penalize you, it will actually reward your site with higher se
rankings. Word press has a plugin that (I think) will in the meta-data for you. As far as content fresh content rules but you also need to have good inbound links depending on the difficulty of teh keywords you are targetting.