Yes, a lot of MBTI personality test interpretations do say that INFJ's are really rare. Then again, people always have a tendency to believe that their type is better or unique than anyone else's.
I haven't met another INFJ in my my circle of friends yet. Which is why I find it amazing how that is the case for you. Based on my understanding, you are surrounded with friends who are undying advocates, wanting to leave the world better than they found it. That's pretty interesting.
I'll try to include an answer to your query if ever I find time to make a post about MBTI. SO far I have none haha. Thanks for reading my entry ate @thegaillery!