No | Year | Proton mass ´ 1027, kg | Achieved relative uncertainty | References |
1 | 1999 | 1.6726217161 |
| [9] |
2 | 2005 | 1.6726217129 |
| [10] |
3 | 2008 | 1.6726216378 |
| [11] |
4 | 2008 | 1.6726217162 |
| [12] |
5 | 2012 | 1.6726217777 |
| [13] |
6 | 2014 | 1.6726218982 |
| [14] |
7 | 2017 | 1.6726217154 |
| [15] |