Total and average citations of articles from the five countries
| Year | USA | UK | Japan | Germany | MC |
|---|---|---|---|---|---|
| 2005 | 79 575 | 13 760 | 9455 | 9386 | 1348 |
| 2006 | 78 313 | 12 996 | 8943 | 11 592 | 1483 |
| 2007 | 71 782 | 13 202 | 7624 | 9287 | 1987 |
| 2008 | 62 347 | 13 924 | 6089 | 9619 | 2536 |
| 2009 | 54 476 | 10 722 | 5989 | 8886 | 3487 |
| 2010 | 45 068 | 9683 | 4892 | 8150 | 3275 |
| 2011 | 36 709 | 9954 | 4135 | 6303 | 4147 |
| 2012 | 27 476 | 7898 | 3380 | 4414 | 3683 |
| 2013 | 17 455 | 7447 | 2011 | 3234 | 2598 |
| 2014 | 8162 | 4913 | 1226 | 1405 | 1243 |
| Total citations | 481 363 | 104 499 | 53 744 | 72 276 | 25 787 |
| Average citations | 27.63 | 35.52 | 11.68 | 18.76 | 2.49 |
MC, Mainland China.