When you think about your goal for SEO, don't just think about the top of the funnel and how many more visits you're getting to your website. Think about your full marketing funnel and how much quality traffic you're getting to your website.
Are the people who are finding your website through SEO actually qualified prospects for your business? If not, does it really matter that the traffic to your website has increased?
As you create your goals, consider what general traffic vs. quality traffic means to you. Set goals not just based on traffic, but based on the entirety of your marketing funnel.