Development of the number of indexed sources and documents in BASE since January 2005.

| Month | Documents | Sources |
|---|---|---|
| January 2005 | 769,642 | 31 |
| March 2005 | 817,581 | 49 |
| May 2005 | 1,501,826 | 56 |
| July 2005 | 2,156,283 | 102 |
| September 2005 | 2,363,351 | 130 |
| November 2005 | 2,417,983 | 160 |
| January 2006 | 2,396,891 | 189 |
| March 2006 | 2,778,099 | 201 |
| May 2006 | 2,979,849 | 224 |
| July 2006 | 3,359,711 | 240 |
| September 2006 | 3,855,144 | 270 |
| November 2006 | 4,042,619 | 283 |
| January 2007 | 4,510,934 | 320 |
| March 2007 | 5,397,884 | 405 |
| May 2007 | 5,531,805 | 417 |
| July 2007 | 7,078,610 | 447 |
| September 2007 | 7,127,670 | 463 |
| November 2007 | 7,336,893 | 502 |
| January 2008 | 7,347,568 | 527 |
| March 2008 | 8,454,810 | 638 |
| May 2008 | 10,103,232 | 767 |
| July 2008 | 12,433,625 | 903 |
| September 2008 | 12,733,728 | 954 |
| November 2008 | 13,556,388 | 977 |
| January 2009 | 14,801,478 | 1027 |
| March 2009 | 18,372,311 | 1191 |
| May 2009 | 19,630,356 | 1242 |
| July 2009 | 20,517,820 | 1284 |
| September 2009 | 21,285,168 | 1346 |
| November 2009 | 21,514,939 | 1374 |