| Similarity | Rank | |
|---|---|---|
| quarter-century | 0.878 | 79790 |
| decades | 0.814 | 2346 |
| decade | 0.812 | 2984 |
| twentieth | 0.757 | 14125 |
| century's | 0.725 | 54113 |
| mid-20th | 0.718 | 75724 |
| decade-long | 0.717 | 60294 |
| decade's | 0.715 | 66905 |
| 1960s | 0.694 | 7911 |
| decades-long | 0.691 | 62316 |
| mid-1960s | 0.686 | 63672 |
| mid-1970s | 0.686 | 53815 |
| twenty-year | 0.683 | 97910 |
| 1970s | 0.681 | 7314 |
| mid-1950s | 0.679 | 83299 |
| 1980s | 0.676 | 7178 |
| nineteenth | 0.676 | 15827 |
| 1950s | 0.675 | 9648 |
| century | 0.669 | 1422 |
| era's | 0.663 | 81740 |
| mid-nineteenth | 0.662 | 88557 |
| 1990s | 0.660 | 7471 |
| 40-year | 0.660 | 56085 |
| heyday | 0.659 | 29800 |
| history's | 0.659 | 51268 |