The relation between visits and earnings is really hard to preview. I had months with little traffic from search engines but I made much more money than in others. That’s because I had some very few players that made a lot of spending.
It is really very different the above realtion when you’re receiving traffic for words like “no deposit casinos” and “casino reviews” for example. It’s a matter of quality of traffic. A few quality traffic may worth more than 100X more traffic but with no quality.