Table:
text: 1963 Formula One season
Non-Championship race results
Non-Championship race results
_ Race_Name Circuit Date_ Winning_driver Constructor_ Report
1 IV Lombank Trophy Snetterton 30 March Graham Hill BRM Report
2 XXIII Pau Grand Prix Pau 15 April Jim Clark Lotus - Climax Report
3 XI Glover Trophy Goodwood 15 April Innes Ireland Lotus - BRM Report
4 IV Gran Premio Citta di Imola Imola 21 April Jim Clark Lotus - Climax Report
5 XIV Gran Premio di Siracusa Syracuse 25 April Jo Siffert Lotus - BRM Report
6 XIX BARC Aintree 200 Aintree 27 April Graham Hill BRM Report
7 XVI BRDC International Trophy Silverstone 11 May Jim Clark Lotus - Climax Report

Question: On how many dates is the 1963 Formula One season at Silverstone circuits among non-championship race results?

Question: How many constructors are listed for the non-championship racing results of the 1963 Formula One season in the BRDC International Trophy of Race XVI?