The rankings are almost certainly based upon WTBTS of Britain accounts for the year ended Aug 2015, and the IBSA accounts for the same date.
i was going to do a separate post on these accounts (and the Kingdom Hall Trust), but it is a big task, and I didn't have the time. The accounts are complicated, and opaque.
Nevertheless, the mystery here is easily solved.
"Voluntary income" for WTBTS increased from £35,525,338 to £61,030,638. Hence the increase from 70th to 19th.
"Voluntary income" for IBSA increased from £22,500,616 to £32,289,275. Hence the increase from 202nd to 130th.
In both cases, my interpretation of the accounts is that the increase is the result of the "new arrangements" under which all the congregations willingly donated their accumulated funds above a certain amount. The accounts don't breakdown what proportion of the voluntary income comes from this snatch and run "new arrangement", but given "Voluntary income" in the "Restricted fund" category actually decreased over the same period (from £1,606,031 to £390,051), I would guess that actual donations from the drones have been on the decrease, perhaps a significant decrease.
If I am right, the "increase" is nothing more than the Borg using up its internal savings, at a considerable rate, but this is not immediately apparent, because the accounts for WTBTS and IBSA are separate from the accounts of each individual congregation.
I did see the Aust accounts at one stage, and it did look like the increase could be similarly explained.