I have been studying with Duolingo for the past year (about 30,000 points) and have achieved 65% fluency. This number has not changed in the last 2 months despite receiving about 80 points per day. I am at level 24. Is there an upper limit on fluency with the program?
The fluency "meter" is only a notional figure - - you will find out your true fluency level only when you use the language (not just Spanish) to try speaking with a native speaker.
But stress not! it will disappear soon as a feature when you get switched over to the new Spanish course tree - - we all will be eventually, and I believe it's more challenging and gets you towards higher levels as well.
[my daft wee DL blog and meanderings through DL and Spanish ]