| Year of Joining System | City | % Correct |
|---|---|---|
| 1883 | Austin | 99%
|
| 1969 | San Antonio | 94%
|
| 1969 | Richardson (Dallas) | 93%
|
| 1967 | El Paso | 89%
|
| 1965 | Arlington | 76%
|
| 2005 | Rio Grande Valley | 50%
|
| 1979 | Tyler | 50%
|
| 1973 | Odessa (Permian Basin) | 46%
|