Table:
text: Arturo Merzario
Complete Formula One World Championship results
Complete Formula One World Championship results
Year_ Entrant Chassis Engine Points
1978 Team Merzario Merzario A1 Cosworth V8 0
1979 Team Merzario Merzario A1B Cosworth V8 0
1979 Team Merzario Merzario A2 Cosworth V8 0
1979 Team Merzario Merzario A4 Cosworth V8 0

Question: At Arturo Merzario, what is the average year for a Merzario A2 chassis?