How automatic are backport package updates?

[Gregg Nemas <gnemas@gmail.com>]

When a package is added to an official backports repository, what
determines when it gets updated? For example, I noticed that for the
package KMyMoney, the period between entering unstable and migrating
to testing seems to be always 5 days, but the period from entering
testing to entering backports seems to be highly variable. For version
5.0.8-1, it was over two months, but for 5.1.0-1 it was only seven
days. The latest, 5.1.1-1, entered testing on Dec 26, but still has
not shown up in backports.

Version 5.0.8-1
Jan 25 Accepted into unstable
Jan 30 Migrated to testing
Apr 6 Accepted into backports

Version 5.1.0-1
Jun 15 Accepted into unstable
Jun 20 Migrated to testing
Jun 27 Accepted into backports

Version 5.1.1-1
Dec 21 Accepted into unstable
Dec 26 Migrated to testing
??? Accepted into backports

Thanks,

Gregg