Table:
text: 1998 Austrian Grand Prix
Classification
Classification
Driver Constructor_ Laps Time_Retired Grid
Mika Häkkinen McLaren - Mercedes 71 1:30:44.086 3
David Coulthard McLaren - Mercedes 71 +5.289 14
Michael Schumacher Ferrari 71 +39.092 4
Eddie Irvine Ferrari 71 +43.976 8
Ralf Schumacher Jordan - Mugen-Honda 71 +50.654 9
Jacques Villeneuve Williams - Mecachrome 71 +53.202 11
Damon Hill Jordan - Mugen-Honda 71 +1:13.624 15
Johnny Herbert Sauber - Petronas 70 +1 lap 18
Alexander Wurz Benetton - Playlife 70 +1 lap 17
Jarno Trulli Prost - Peugeot 70 +1 lap 16
Shinji Nakano Minardi - Ford 70 +1 lap 21
Ricardo Rosset Tyrrell - Ford 69 +2 laps 22

Question: What is the average starting grid for Johnny Herbert with a time/lag +1 lap in the 1998 Austrian Grand Prix?