Depends on dozens of other factors such as competition, your on page seo, the types of links you have, the keywords you're trying to rank for etc.

What sorrellaff said, also you should not rely on a single source of traffic.
If Google decides to change its algorithm one day, you may lose a lot of ranking and end up with no traffic at all.
Diversify through organic search engine traffic, social media traffic, guest blog post traffic and any and all other traffic you can think of.

OK thanks for your advice everyone. It has definitely helped!

Write articles and do concentrate on keywords on your articles.This gives most power.
And this increase backlinks as well.

People focus too much on backlinks. I have a site with over 15,000 pages and 0 backlinks. I get over 1000 visits a day and on this one site alone, I'll make over $200 in AdSense this month. Content is king. My secret is using content that nobody else has which creates thousands of long tail keywords that nobody else has. No matter how Google changes their algorithm, if you are in sole possession of thousands of long tail keywords, your results will always be at the top of Google. Backlinks are work that I'll never do.

it depends on the quality of the backlink. I have paid a company for 4k link for one of my site and i don't think it increased any traffic of my site. They have created a new profile in 4000 sites and added my url there. But if you can put backlink high google ranking sites, your alexa ranking will be better.