Science Decrees That This Is The Average Pen15 Size

A systematic review of flaccid and erect penis length and circumference in up to 15,521 men – or, aptly enough, the world’s largest ever survey of The D – compiled by medical journal BJU International has decreed that the average penis length is 5.16 inches (or 13.1cm) when standing to full attention. 

Congratulations/sorry for your loss.
Published yesterday to your great interest, evidently, Am I Normal was conducted with the aim that such an all encompassing look at 8===D might be useful in clinical and therapeutic settings to counsel men with crippling peen anxiety and resulting cases of body dysmorphia, for academic research and also for blogs with daily dick joke quotas that need to be met on punishment of severance. 
To reach that conclusion, men aged between 17 and 91 were surveyed by health professionals across Europe, Asia, Africa and the United States. Findings from twenty other pen15 studies were accumulated, and their results were compiled in five comparative nomographs, like the one below. 
Wow. Look at all this science: 
via Slate
More easily interpreted conclusions that may also be of interest to you include – but are not strictly limited to – there being no correlation between penis size and shoe size or index finger length; 85% of women were also reportedly satisfied with the size of their partner’s member; and while only 15% of women reported saying that the length of one’s boner is important, girth is, in general, more important than length. You can take in the full study here. 
The more you know.