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:
| # | Race Name | Circuit | Date | Winning driver | Constructor | Report |
| --- | --- | --- | --- | --- | --- | --- |
| 1.0 | IV Lombank Trophy | Snetterton | 30 March | Graham Hill | BRM | Report |
| 2.0 | XXIII Pau Grand Prix | Pau | 15 April | Jim Clark | Lotus - Climax | Report |
| 3.0 | XI Glover Trophy | Goodwood | 15 April | Innes Ireland | Lotus - BRM | Report |
| 4.0 | IV Gran Premio Citta di Imola | Imola | 21 April | Jim Clark | Lotus - Climax | Report |
| 5.0 | XIV Gran Premio di Siracusa | Syracuse | 25 April | Jo Siffert | Lotus - BRM | Report |
| 6.0 | XIX BARC Aintree 200 | Aintree | 27 April | Graham Hill | BRM | Report |
| 7.0 | XVI BRDC International Trophy | Silverstone | 11 May | Jim Clark | Lotus - Climax | Report |
| 8.0 | XV Gran Premio di Roma | Vallelunga | 19 May | Bob Anderson | Lola - Climax | Report |
| 9.0 | III Solituderennen | Solitudering | 28 July | Jack Brabham | Brabham - Climax | Report |
| 10.0 | XII Kanonloppet | Karlskoga | 11 August | Jim Clark | Lotus - Climax | Report |
| 11.0 | III Mediterranean Grand Prix | Enna Pergusa | 18 August | John Surtees | Ferrari | Report |
| 12.0 | I Austrian Grand Prix | Zeltweg | 1 September | Jack Brabham | Brabham - Climax | Report |
| 13.0 | X International Gold Cup | Oulton Park | 21 September | Jim Clark | Lotus - Climax | Report |
Question:
How many dates have silverstone circuit
Answer:
1.0