It may be a coincidence (but probably not) that the first glyph on this page (a4-7) is the 100th from the start of the 10-group. Evidently a new theme starts here.
- a1-1 -- a1-7 7
1 a1-8 -- a1-15 8 99
2 a1-16 -- a1-23 8
3 a1-24 -- a1-32 9
4 a2-1 -- a2-12 12
5 a2-13 -- a2-23 11
6 a2-24 -- a2-33 10
7 a3-1 -- a3-11 11
8 a3-12 -- a3-18 7
9 a3-19 -- a3-29 11
10 a3-30 -- a4-6 12

Also: 99 happens to characterizes the number of lunations in a Venus cycle:

"After five complete cycles totaling 2,920 days, the movement of Venus fill eight idealized years of 365 days each and come within hours of spanning 99 lunations." (Popol Vuh)