How to reproduce the codebook usage

[BaohaoLiao]

Hi, in the paper, you state "The codebook usage is calculated as the percentage of used codes in the
queue of size 65536 over the whole codebook size." May I ask how to do it? Is it possible to use the released ckeckpoint to reproduce the reported number? like

8 2.19 20.79 0.675 97.0% in Table 2.

Thank you for your help in advance.