Meaning of one figure in Tor Network Status web page

[Pascal Levasseur]

Hello,

I would like to know what is the meaning of the fourth figure (in this
example, the one after 5 and 4) in the data displayed by the Tor Network
Status at serifos.eecs.harvard.edu ?

FR *clearstream           20    5    4    1

Thanks in advance.

Pascal Levasseur