Concentration of minor products in the nitration of nitrobenzene

I was baffled by the concentration of minor products in the nitration of nitrobenzene. 


This is the picture from Solomon Frhyle's book, page $695$:


[![enter image description here](https://i.stack.imgur.com/kcliL.png)](https://i.stack.imgur.com/kcliL.png)


Since nitro is electron withdrawing and meta directing, the high concentration of meta isomer is justified. However, I had predicted the order to be $m>p>o$ because both nitro groups are electron withdrawing and if they are close together they will cause destabilisation by increasing charge density at adjacent places. On the other hand in the para isomer, the nitro groups are far away so development of partial positivity at opposite ends shouldn't be a big problem. 


Could someone explain why the para isomer is less in concentration and how my reasoning is incorrect? 


