| Keyword | CPC | PCC | Volume | Score | Length of keyword |
|---|---|---|---|---|---|
| world's first metro system | 0.94 | 1 | 8282 | 40 | 26 |
| world's | 1.02 | 0.6 | 6143 | 40 | 7 |
| first | 1.22 | 0.6 | 8365 | 1 | 5 |
| metro | 1.23 | 0.4 | 4886 | 93 | 5 |
| system | 1.49 | 0.2 | 1765 | 76 | 6 |
| Keyword | CPC | PCC | Volume | Score |
|---|---|---|---|---|
| world's first metro system | 0.62 | 0.7 | 8606 | 80 |
| first metro in the world | 0.73 | 0.5 | 3704 | 98 |
| which metro is first | 0.99 | 0.8 | 4265 | 84 |
| metro system in the world | 0.5 | 0.2 | 9162 | 46 |
| world's biggest metro system | 0.08 | 0.5 | 5683 | 99 |
| first metro rail in world | 1.92 | 0.5 | 8823 | 68 |
| world's largest metro system | 0.97 | 0.2 | 7197 | 5 |
| oldest metro system in the world | 1.95 | 0.3 | 9629 | 97 |
| world's longest metro system | 0.77 | 0.3 | 7943 | 100 |
| when was the metro invented | 1.48 | 0.9 | 5601 | 11 |
| the history of metro | 0.83 | 0.9 | 1706 | 83 |
| biggest metro system in the world | 0.88 | 0.1 | 9780 | 96 |
| country with the oldest metro system | 1.11 | 0.5 | 4697 | 22 |
| largest metro system in the world | 1.55 | 0.6 | 6594 | 77 |
| where is the oldest metro system | 0.98 | 0.7 | 1820 | 28 |
| overview of metro system | 1 | 0.3 | 827 | 60 |
| the largest metro system | 1.72 | 1 | 1351 | 93 |
| list of metro systems in the world | 0.35 | 0.5 | 8171 | 96 |
