On the Internetlivestats website, they are talking of 3.5 billions searches per day for Google(1). On the duckduckgo website, they are saying they serve 7 millions queries per day(2). So DuckDuckGo does 0.2% of the amount of Google. Please correct me is my logic is flawed.

(1)http://www.internetlivestats.com/google-search-statistics/

(2)https://duckduckgo.com/traffic.html

Yeah. If they went from 1 to 6 users it wouldn't be impressive at all, so "600%" is meaningless by itself.

I think it's pretty meaningful for the exact reasons you state.

If they had gone up millions then they would have used real numbers. Therefore the actual numbers are still pretty low.

Here are the actual numbers:

https://duckduckgo.com/traffic.html

You're wrong. It went up by 5.5 million.