Tokusatsu Network has numbers for 1-18.
http://tokusatsunetwork.com/2014/03/10/tokusatsu-tv-ratings-212-216/
So... Is that good? I suppose it is, considering KR has better numbers than the other two shows...
Kamen Rider Wizard's average series rating between episode 1 to 19 was a 6.06%. It actually did better in ratings than Gaim has been. Wizard managed to keep up at least a 7% average for the first few episodes while Gaim immediately dropped into the 5% range. Gaim didn't even manage to get above a 7% within the first 18 episodes.
Rating numbers have been on the decline for years for a variety of reasons. I'd say Gaim's ratings are still better than nothing.
Don't forget Gaim's Q1 sales were 390% higher than Wizards.
Tokusatsu Network has numbers for 1-18.
http://tokusatsunetwork.com/2014/03/10/tokusatsu-tv-ratings-212-216/
As long if merchandise sales are good then that's what happens. I guess Gaim's ratings are lower then Wizard's because the older fans was turn off by the fruit theme. Kids may still love Kamen Rider, but I hear most of the older fandom stop caring about the series for a while now. Kids are the main target audience, but older people help ratings as well.
Kyoryuger's rating are likely so low since it's just the kids watching the show, the older fans didn't care to watch it.