HONESTLY, how long does sex last on an average night with your SO?

Maybe it's because we are young,and have only been with each other, but after reading some posts on here, I feel like we are severely lacking in stamina. I'm talking like the longest we've gone was about 11 minutes and that's being a little tipsy. On average, less than 2 minutes for us and I feel like that's even a stretch. Maybe closer to 80 seconds. Any advice from the couples with stamina?! 
How long for you & your SO?