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:
| Number | Driver | Entrant | Chassis | Engine | Tyre |
| --- | --- | --- | --- | --- | --- |
| 1 | Jimmy Bryan | Dean Van Lines | Kuzma | Offenhauser | F |
| 2 | John Lawrence | Ecurie Ecosse | Jaguar D-Type | Jaguar | D |
| 4 | Jack Fairman | Ecurie Ecosse | Jaguar D-Type | Jaguar | D |
| 6 | Ninian Sanderson | Ecurie Ecosse | Jaguar D-Type | Jaguar | D |
| 7 | Bob Veith | Bob Estes | Phillips | Offenhauser | F |
| 8 | Jean Behra | Maserati | Maserati 250F | Maserati | F |
| 8 | Jean Behra | Maserati | Maserati 450S1 | Maserati | F |
| 12 | Pat O'Connor | Sumar | Kurtis Kraft 500G | Offenhauser | F |
| 16 | Mario Bornigia | Scuderia Cottione | Ferrari | Ferrari | ? |
| 27 | Tony Bettenhausen | Novi Auto Air Conditioning | Kurtis Kraft 500F | Novi (s/c) | F |
| 35 | Eddie Sachs | Jim Robbins | Kurtis Kraft 500G | Offenhauser | F |
| 49 | Ray Crawford | Meguiar Mirror Glaze | Kurtis Kraft 500G | Offenhauser | F |
| 52 | Troy Ruttman | John Zink | Watson | Offenhauser | F |
| 52 | Jim Rathmann2 | John Zink | Watson | Offenhauser | F |
| 54 | Paul Russo | Novi Auto Air Conditioning | Kurtis Kraft 500F | Novi (s/c) | F |
| 73 | Andy Linden | McNamara Veedol | Kurtis Kraft 500G | Offenhauser | F |
| 98 | Johnnie Parsons | Agajanian | Kuzma | Offenhauser | F |
Question:
how many racers had an offenhauser engine?
Answer:
8