Monthly figures
FITs registration statistics on a month-by-month basis
Monthly registrations
Here are the trends, broken down between domestic and non-domestic installations.
December 2011 was a massive month, thanks to the government's threatened tariff changes. Another mini-boom followed in March when the tariff cuts were delayed by the legal challenge.
So far the amount of new capacity registered for the FITs has increased almost every month. The cumulative capacity is shown below.

There are individual pages for solar, wind, hydro and AD or use the menu on the left.
How up-to-date is the data?
Aaah! Now that is the question. The data available from Ofgem is all based on the date the installation appears on the FIT register, not the date it is commissioned.
There can be substantial delays, though these have recently been reducing - see here.