Study the table below, which shows the life expectancy for selected countries in Central America.
| Country | Guatemala | Honduras | Nicaragua | El Salvador | Costa Rica | Panama |
|---|---|---|---|---|---|---|
| Life Expectancy (years) | 68.5 | 70.5 | 74.0 | 71.0 | 78.5 | 75.5 |
Calculate the mean life expectancy for these countries.