| Coastal area | Breakpoint | Period | Slope |
| Cote d’Ivoire | 1913; 1923; 1971 | 1901-1913 | 59.3 |
| 1914-1923 | −30.9 | ||
| 1924-1971 | 1.79 | ||
| 1972-2013 | −3.4 | ||
| Ghana | 1940; 1980 | 1901-1940 | −0.5 |
| 1941-1980 | −2.3 | ||
| 1981-2013 | 3.2 | ||
| Togo | 1958; 1971 | 1901-1958 | 0.29 |
| 1959-1971 | −14.8 | ||
| 1972-2013 | 2.74 | ||
| Benin | 1967 | 1901-1967 | −0.15 |
| 1968-2013 | 3.23 | ||
| Nigeria | 1906; 1926; 1929 | 1901-1906 | 132 |
| 1907-1926 | −19.6 | ||
| 1927-1929 | −294 | ||
| 1930-2013 | 0.85 |