Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| District | Incumbent | Party | First elected | Result | Candidates |
| --- | --- | --- | --- | --- | --- |
| Illinois 2 | Abner J. Mikva | Democratic | 1968.0 | Re-elected | Abner J. Mikva (D) 74.7% Harold E. Marks (R) 25.3% |
| Illinois 4 | Ed Derwinski | Republican | 1958.0 | Re-elected | Ed Derwinski (R) 68.0% Melvin W. Morgan (D) 32.0% |
| Illinois 7 | Frank Annunzio | Democratic | 1964.0 | Re-elected | Frank Annunzio (D) 87.3% Thomas J. Lento (R) 12.7% |
| Illinois 9 | Sidney R. Yates | Democratic | 1964.0 | Re-elected | Sidney R. Yates (D) 75.8% Edward Wolbank (R) 24.2% |
| Illinois 12 | Robert McClory | Republican | 1962.0 | Re-elected | Robert McClory (R) 62.1% James J. Cone (D) 37.9% |
| Illinois 13 | Phil Crane | Republican | 1969.0 | Re-elected | Phil Crane (R) 58.0% Edward A. Warman (D) 42.0% |
| Illinois 18 | Robert H. Michel | Republican | 1956.0 | Re-elected | Robert H. Michel (R) 66.1% Rosa Lee Fox (D) 33.9% |
| Illinois 19 | Tom Railsback | Republican | 1966.0 | Re-elected | Tom Railsback (R) 68.2% James L. Shaw (D) 31.8% |
| Illinois 20 | Paul Findley | Republican | 1960.0 | Re-elected | Paul Findley (R) 67.5% Billie M. Cox (D) 32.5% |
| Illinois 21 | Kenneth J. Gray | Democratic | 1954.0 | Re-elected | Kenneth J. Gray (D) 62.5% Fred Evans (R) 37.5% |
Question:
how many times was it the district illinois 18?
Answer:
1.0