The estimated number of taxpayer's records taken in a breach the IRS waited until May 2015 to confirm has been revised from nearly 100,000 to roughly 720,000 in a new figure (archived). In August 2015 the figure was quietly revised upwards to 330,000 records. The substantial increase coming with each new revised figure for a single breach suggests the IRS has no idea how many records have been accessed, and they are further incapable of knowing until they have been scammed. Sorry for your loss.