On July 28, the Population Reference Bureau (PRB) published its annual World Population Data Sheet, which is widely considered to be the most accurate source of information on population. PRB estimates world population for mid-2010 is now just under 6.9 billion and that it will reach the 7.0 billion mark next year, just twelve years after the 6.0 billion mark was reached.
PRB projected that world population will be 9.485 billion by mid-2050, just shy of 9.5 billion. That number is slightly higher than last year’s projection (9.421 billion), and notably higher than the U.N.’s current medium variant projection (9.149 billion), as reported in World Population Prospects: the 2008 Revision.
http://blog.populationinstitute.org/2010/07/28/9-5-billion/
http://www.prb.org/pdf10/10wpds_eng.pdf