A blog post would be better if you know the keyword that you would like to optimized. So I would like to share you Another SEO keyword Analysis Tools that I have found. It is called live keyword analysis .
The site has the ability to know the percentage of your keyword in your post. You just have to do the following :
Know your Top 3 keyword to be optimized and type on the space provided.
Write Your post
Copy and paste your post on the space provided.
Finished. There you have it, They will give the percentage of your keywords within your post. I think this is a nice and neat tool that an SEO Practitioner should know.