Here are my estimates by using SS sales since last certification dates. It's not quite up to date anymore but it's something.
Boy - 1.013.000 (RIAA 1995 1.000.000 + Soundscan 2005-2006 13.000)
October - 1.009.000 (RIAA 1995 1.000.000 + SS 2005-2006 9.000)
War - 4.146.000 (RIAA 1995 4.000.000 + SS 1998 44.000 + SS 2003-2006 102.000)
UABRS - 3.008.000 (RIAA 1994 3.000.000 + SS 2008 8.000)
Unforgettable Fire -3.000.000 (RIAA 1995)
WAIA - 1.000.000 (RIAA 1994)
The Joshua Tree - 10.531.000 (RIAA 1995 10.000.000 + SS 1998 104.000 + SS 2002 12.000 + SS 2003-2008 415.000)
Rattle & Hum - 5.125.000 (RIAA 1995 5.000.000 + SS 1998 43.000 + SS 2003-2006 82.000)
Achtung Baby - 8.150.000 (RIAA 1997 8.000.000 + SS 1998 40.000 + SS 2003-2006
110.000)
Zooropa - 2.332.000 (Soundscan 2006)
Pop - 1.497.000 (Soundscan 2006)
BO 80-90 (2cd) - 1.400.000 (Soundscan 2005)
BO 80-90 - 3.063.000 (Soundscan 2009)
ATYCLB - 4.300.000 (Soundscan 2006)
BO 90-00 (combined) - 1.267.000 (Soundscan 2006)
HTDAAB - 3.213.000 (Soundscan 2007)
18 Singles - 964.000 (Soundscan 2009)
Live from paris (digital) - 14.000 (Soundscan 2008)
Total: 55.032.000 but it could me more. The Joshua Tree and The Best of 1980-1990 especially are undercertified. I hope there are some more Soundscan or RIAA updates for the other albums soon.