| Ethnic group | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 |
| White | 328,013 | 345,300 | 377,873 | 413,570 | 450,979 | 447,206 |
| Black | 23,977 | 26,492 | 32,657 | 38,490 | 45,278 | 48,780 |
| Asian | 41,870 | 42,361 | 46,534 | 50,585 | 56,078 | 59,081 |
| Mixed | 11,822 | 13,492 | 15,455 | 17,518 | 19,858 | 21,028 |
| Other | 4,681 | 5,139 | 5,159 | 5,592 | 6,461 | 6,819 |
| Unknown | 21,833 | 21,364 | 24,783 | 18,530 | 8,167 | 6,436 |
| Total | 432,196 | 454,148 | 502,461 | 544,285 | 586,821 | 589,350 |
| Ethnic group | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 |
| White | 262,507 | 277,767 | 306,043 | 326,235 | 331,491 | 333,198 |
| Black | 16,808 | 18,694 | 23,014 | 25,244 | 27,162 | 29,688 |
| Asian | 33,551 | 34,074 | 37,286 | 39,169 | 40,737 | 43,211 |
| Mixed | 9,285 | 10,715 | 12,139 | 13,307 | 14,185 | 15,494 |
| Other | 3,541 | 3,869 | 3,878 | 4,056 | 4,419 | 4,709 |
| Unknown | 19,872 | 19,425 | 22,664 | 17,052 | 6,640 | 4,935 |
| Total | 345,564 | 364,544 | 405,024 | 425,063 | 424,634 | 431,235 |
| Ethnic group | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 |
| White | 75.9% | 76.0% | 75.2% | 76.0% | 76.9% | 75.9% |
| Black | 5.5% | 5.8% | 6.5% | 7.1% | 7.7% | 8.3% |
| Asian | 9.7% | 9.3% | 9.3% | 9.3% | 9.6% | 10.0% |
| Mixed | 2.7% | 3.0% | 3.1% | 3.2% | 3.4% | 3.6% |
| Other | 1.1% | 1.1% | 1.0% | 1.0% | 1.1% | 1.2% |
| Unknown | 5.1% | 4.7% | 4.9% | 3.4% | 1.4% | 1.1% |
| Total | 100.0% | 100.0% | 100.0% | 100.0% | 100.0% | 100.0% |
| Ethnic group | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 |
| White | 76.0% | 76.2% | 75.6% | 76.7% | 78.1% | 77.3% |
| Black | 4.9% | 5.1% | 5.7% | 5.9% | 6.4% | 6.9% |
| Asian | 9.7% | 9.3% | 9.2% | 9.2% | 9.6% | 10.0% |
| Mixed | 2.7% | 2.9% | 3.0% | 3.1% | 3.3% | 3.6% |
| Other | 1.0% | 1.1% | 1.0% | 1.0% | 1.0% | 1.1% |
| Unknown | 5.8% | 5.3% | 5.6% | 4.0% | 1.6% | 1.1% |
| Total | 100.0% | 100.0% | 100.0% | 100.0% | 100.0% | 100.0% |
| Ethnic origin | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 |
| White | 328,013 | 345,300 | 377,873 | 413,570 | 450,979 | 447,206 |
| Black African | 16,120 | 18,129 | 22,820 | 27,543 | 32,960 | 36,340 |
| Black Caribbean | 6,321 | 6,773 | 8,138 | 9,144 | 10,286 | 10,383 |
| Black Other | 1,536 | 1,590 | 1,699 | 1,803 | 2,032 | 2,057 |
| Asian Bangladeshi | 3,964 | 4,042 | 4,612 | 5,249 | 5,823 | 6,323 |
| Asian Chinese | 3,935 | 4,101 | 4,323 | 4,246 | 4,501 | 4,541 |
| Asian Indian | 16,977 | 16,582 | 17,217 | 18,183 | 19,065 | 19,534 |
| Asian Pakistani | 11,705 | 12,021 | 7,087 | 14,575 | 16,831 | 18,010 |
| Asian Other | 5,289 | 5,615 | 13,295 | 8,332 | 9,858 | 10,673 |
| Mixed - White and Asian | 3,755 | 4,199 | 4,729 | 5,278 | 5,920 | 6,210 |
| Mixed - White and Black African | 1,376 | 1,520 | 1,769 | 2,172 | 2,343 | 2,599 |
| Mixed - White and Black Caribbean | 2,845 | 3,463 | 4,225 | 4,940 | 5,811 | 6,044 |
| Mixed - Other mixed background | 3,846 | 4,310 | 4,732 | 5,128 | 5,784 | 6,175 |
| Other ethnic background | 4,681 | 5,139 | 5,159 | 5,592 | 6,461 | 6,819 |
| Unknown | 21,833 | 21,364 | 24,783 | 18,530 | 8,167 | 6,436 |
| Total | 432,196 | 454,148 | 502,461 | 544,285 | 586,821 | 589,350 |
| Ethnic origin | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 |
| White | 262,507 | 277,767 | 306,043 | 326,235 | 331,491 | 333,198 |
| Black African | 10,973 | 12,556 | 15,809 | 17,643 | 19,247 | 21,427 |
| Black Caribbean | 4,725 | 4,982 | 5,982 | 6,383 | 6,683 | 6,914 |
| Black Other | 1,110 | 1,156 | 1,223 | 1,218 | 1,232 | 1,347 |
| Asian Bangladeshi | 3,147 | 3,249 | 3,705 | 4,040 | 4,308 | 4,685 |
| Asian Chinese | 3,311 | 3,496 | 3,617 | 3,434 | 3,472 | 3,605 |
| Asian Indian | 14,066 | 13,815 | 14,256 | 14,723 | 14,388 | 14,906 |
| Asian Pakistani | 9,012 | 9,283 | 5,311 | 11,033 | 11,908 | 12,710 |
| Asian Other | 4,015 | 4,231 | 10,397 | 5,939 | 6,661 | 7,305 |
| Mixed - White and Asian | 3,045 | 3,468 | 3,858 | 4,094 | 4,492 | 4,823 |
| Mixed - White and Black African | 1053 | 1,175 | 1,325 | 1,601 | 1,556 | 1,852 |
| Mixed - White and Black Caribbean | 2,171 | 2,705 | 3,265 | 3,746 | 4,072 | 4,409 |
| Mixed - Other mixed background | 3,016 | 3,367 | 3,691 | 3,866 | 4,065 | 4,410 |
| Other ethnic background | 3,541 | 3,869 | 3,878 | 4,056 | 4,419 | 4,709 |
| Unknown | 19,872 | 19,425 | 22,664 | 17,052 | 6,640 | 4,935 |
| Total | 345,564 | 364,544 | 405,024 | 425,063 | 424,634 | 431,235 |
| Ethnic origin | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 |
| White | 75.9% | 76.0% | 75.2% | 76.0% | 76.9% | 75.9% |
| Black African | 3.7% | 4.0% | 4.5% | 5.1% | 5.6% | 6.2% |
| Black Caribbean | 1.5% | 1.5% | 1.6% | 1.7% | 1.8% | 1.8% |
| Black Other | 0.4% | 0.4% | 0.3% | 0.3% | 0.3% | 0.3% |
| Asian Bangladeshi | 0.9% | 0.9% | 0.9% | 1.0% | 1.0% | 1.1% |
| Asian Chinese | 0.9% | 0.9% | 0.9% | 0.8% | 0.8% | 0.8% |
| Asian Indian | 3.9% | 3.7% | 3.4% | 3.3% | 3.2% | 3.3% |
| Asian Pakistani | 2.7% | 2.6% | 1.4% | 2.7% | 2.9% | 3.1% |
| Asian Other | 1.2% | 1.2% | 2.6% | 1.5% | 1.7% | 1.8% |
| Mixed - White and Asian | 0.9% | 0.9% | 0.9% | 1.0% | 1.0% | 1.1% |
| Mixed - White and Black African | 0.3% | 0.3% | 0.4% | 0.4% | 0.4% | 0.4% |
| Mixed - White and Black Caribbean | 0.7% | 0.8% | 0.8% | 0.9% | 1.0% | 1.0% |
| Mixed - Other mixed background | 0.9% | 0.9% | 0.9% | 0.9% | 1.0% | 1.0% |
| Other ethnic background | 1.1% | 1.1% | 1.0% | 1.0% | 1.1% | 1.2% |
| Unknown | 5.1% | 4.7% | 4.9% | 3.4% | 1.4% | 1.1% |
| Total | 100.0% | 100.0% | 100.0% | 100.0% | 100.0% | 100.0% |
| Ethnic origin | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 |
| White | 76.0% | 76.2% | 75.6% | 76.7% | 78.1% | 77.3% |
| Black African | 3.2% | 3.4% | 3.9% | 4.2% | 4.5% | 5.0% |
| Black Caribbean | 1.4% | 1.4% | 1.5% | 1.5% | 1.6% | 1.6% |
| Black Other | 0.3% | 0.3% | 0.3% | 0.3% | 0.3% | 0.3% |
| Asian Bangladeshi | 0.9% | 0.9% | 0.9% | 1.0% | 1.0% | 1.1% |
| Asian Chinese | 1.0% | 1.0% | 0.9% | 0.8% | 0.8% | 0.8% |
| Asian Indian | 4.1% | 3.8% | 3.5% | 3.5% | 3.4% | 3.5% |
| Asian Pakistani | 2.6% | 2.5% | 1.3% | 2.6% | 2.8% | 2.9% |
| Asian Other | 1.2% | 1.2% | 2.6% | 1.4% | 1.6% | 1.7% |
| Mixed - White and Asian | 0.9% | 1.0% | 1.0% | 1.0% | 1.1% | 1.1% |
| Mixed - White and Black African | 0.3% | 0.3% | 0.3% | 0.4% | 0.4% | 0.4% |
| Mixed - White and Black Caribbean | 0.6% | 0.7% | 0.8% | 0.9% | 1.0% | 1.0% |
| Mixed - Other mixed background | 0.9% | 0.9% | 0.9% | 0.9% | 1.0% | 1.0% |
| Other ethnic background | 1.0% | 1.1% | 1.0% | 1.0% | 1.0% | 1.1% |
| Unknown | 5.8% | 5.3% | 5.6% | 4.0% | 1.6% | 1.1% |
| Total | 100.0% | 100.0% | 100.0% | 100.0% | 100.0% | 100.0% |