According to NameBio..
There haven't been any NNN.cc sales this year.. 2014 ranged as low as $568 and as high as $6,900.. But, the average was roughly low $XXXX (6 logged sales)....
There has been 1 NNNN.cc reported sale this year (5577.cc) for $1,059...It appears there were quite a few more of these last year (32) and most were in the low $XXX range.
NN.cc doesn't show any reported sale since back in 2010... Out of 4 reported sales 2 were in the $1500-$2000 range, and 2 were above $5000.