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 | Results | Candidates |
| --- | --- | --- | --- | --- | --- |
| Pennsylvania 1 | Bob Brady | Democratic | May 19, 1998 (special) | Re-elected | Bob Brady (D) 81% William Harrison (R) 17% |
| Pennsylvania 2 | Chaka Fattah | Democratic | 1994 | Re-elected | Chaka Fattah (D) 86% Anne Marie Mulligan (R) 14% |
| Pennsylvania 3 | Robert Borski | Democratic | 1982 | Re-elected | Robert Borski (D) 60% Charles Dougherty (R) 40% |
| Pennsylvania 4 | Ron Klink | Democratic | 1992 | Re-elected | Ron Klink (D) 64% Mike Turzai (R) 36% |
| Pennsylvania 6 | Tim Holden | Democratic | 1992 | Re-elected | Tim Holden (D) 61% John Meckley (R) 39% |
| Pennsylvania 7 | Curt Weldon | Republican | 1986 | Re-elected | Curt Weldon (R) 72% Martin D'Urso (D) 28% |
| Pennsylvania 8 | Jim Greenwood | Republican | 1992 | Re-elected | Jim Greenwood (R) 64% Bill Tuthill (D) 33% |
| Pennsylvania 9 | Bud Shuster | Republican | 1972 | Re-elected | Bud Shuster (R) unopposed |
| Pennsylvania 10 | Joe McDade | Republican | 1962 | Retired Republican hold | Don Sherwood (R) 49% Patrick Casey (D) 49% |
| Pennsylvania 11 | Paul Kanjorski | Democratic | 1984 | Re-elected | Paul Kanjorski (D) 67% Stephen Urban (R) 33% |
| Pennsylvania 12 | John Murtha | Democratic | 1974 | Re-elected | John Murtha (D) 68% Timothy Holloway (R) 32% |
| Pennsylvania 13 | Jon D. Fox | Republican | 1994 | Lost re-election Democratic gain | Joe Hoeffel (D) 52% Jon D. Fox (R) 47% |
| Pennsylvania 14 | William Coyne | Democratic | 1980 | Re-elected | William Coyne (D) 61% Bill Ravotti (R) 39% |
| Pennsylvania 15 | Paul McHale | Democratic | 1992 | Retired Republican gain | Pat Toomey (R) 55% Roy Afflerbach (D) 45% |
| Pennsylvania 16 | Joe Pitts | Republican | 1996 | Re-elected | Joe Pitts (R) 71% Robert Yorczyk (D) 29% |
| Pennsylvania 17 | George Gekas | Republican | 1982 | Re-elected | George Gekas (R) unopposed |
| Pennsylvania 18 | Mike Doyle | Democratic | 1994 | Re-elected | Mike Doyle (D) 68% Dick Walker (R) 32% |
| Pennsylvania 19 | Bill Goodling | Republican | 1974 | Re-elected | Bill Goodling (R) 68% Linda Ropp (D) 29% |
| Pennsylvania 20 | Frank Mascara | Democratic | 1994 | Re-elected | Frank Mascara (D) unopposed |
Question:
How many incumbents were first elected in 1984? 
Answer:
1.0