Yes, there are plenty of sources for this figure.  Here are a few.  I’ll also include links for you to see more of the sources yourself.  
Astrophysicists, and people that study astronomy at other institutions have done a lot of surveys to try to get a feel for the range of possible numbers.  If I’m not mistaken, there’s one survey that says there’s less than 1%, but the lower bound of that survey isn’t clear.  Other surveys put it at around 3%, but that includes life of microbial or lichen-like dimensions.
assitant
The LHC, of course.
assistant
What are the current odds that there is intelligent life in our galaxy?
user
The numbers I’m getting from astrophysical estimates are currently less than 1%.
assistant
Do you have a source?
user