An experiment was conducted to investigate the rate of reaction between magnesium ribbon and dilute sulfuric acid. The volume of hydrogen gas released was monitored at regular intervals.

| Time in minutes | Volume of hydrogen in cm3\text{cm}^3cm3 |
|---|---|
| 0 | 0 |
| 1 | 24 |
| 2 | 42 |
| 3 | 54 |
| 4 | 62 |
| 5 | 66 |
| 6 | 68 |
| 7 | 68 |
Calculate the mean rate of production of hydrogen gas over the first 180 seconds, in cm3/s\text{cm}^3/\text{s}cm3/s.