I recently found a contradiction between the life expectancies of a Hobbit. A Hobbit comes of age at around 33 years old. Comparing that with a human, we come of age at around 18. Sidetracking a little, the WHO states that the average human life expectancy is about 77.5 years, which I will round up to 78.
In that sense, by the time an average human is 18, he has lived about 23% of his/her lives. In the medieval times, this percentage would be lower (considering that humans would be 'adult' at smaller ages). Now, if we assume that Hobbits have a similar system, with them having completed 20-25% of their lives by 33 (which seems reasonable enough), we get that the average Hobbit would live up to be 132-165 years old.
Here's where the contradiction comes up: In Fellowship Of the Ring, the first chapter, The Long Expected Party, we have this line:
Bilbo was going to be elewenty-one, 111, a rather curious number, and a very respectable age for a hobbit (the Old Took himself had only reached 130);
I take that the Old Took is the oldest living Hobbit. In this sense, he lived 2 years short of the above calculated life expectancy. Bilbo had lived to only 111, and is proclaimed as being rather curious. With this statement, I think we can say with a pretty good estimation that Hobbits are more like humans with a life expectancy of around 70-80 years.
So, what is the average life expectancy of a Hobbit. A lower number with ridiculously high 'comin-of-age' standards, or a high number which no one has ever reached. Of course, I know all of this may seem ambiguous and eyebrow-raising, but is there any real source anywhere in the texts which say how long Hobbits live?