There's most likely more people who ctb using the information on this site than we think. I doubt that the majority of them even made an account here in the first place. But, anyway, a crossed out username doesn't necessarily mean that they ctb as it could be a self ban due to the site harming them more than it makes then feel better or perhaps they fully recovered and left as they no longer need this site.
I personally think that the inactive users who aren't crossed out are more suspicious to have CTB than the crossed out users as not everybody will want to post a goodbye thread here. I certainly won't as I personally find it repulsive at how people care more about a user just when they're going to die as opposed to caring about them whilst they're alive. I guess it can't be helped as it's just human nature but I personally would be infuriated with seeing people who were ignoring me before suddenly care about me when I'm going to kill myself.
In short, the number of people who used this site to ctb is definitely higher than we think