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:
| Grand Prix | Date | Location | Pole Position | Fastest Lap | Winning Driver | Constructor | Report |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Brazilian Grand Prix | 26 March | Jacarepaguá | Ayrton Senna | Riccardo Patrese | Nigel Mansell | Ferrari | Report |
| San Marino Grand Prix | 23 April | Imola | Ayrton Senna | Alain Prost | Ayrton Senna | McLaren - Honda | Report |
| Monaco Grand Prix | 7 May | Monaco | Ayrton Senna | Alain Prost | Ayrton Senna | McLaren - Honda | Report |
| Mexican Grand Prix | 28 May | Hermanos Rodríguez | Ayrton Senna | Nigel Mansell | Ayrton Senna | McLaren - Honda | Report |
| United States Grand Prix | 4 June | Phoenix | Ayrton Senna | Ayrton Senna | Alain Prost | McLaren - Honda | Report |
| Canadian Grand Prix | 18 June | Circuit Gilles Villeneuve | Alain Prost | Jonathan Palmer | Thierry Boutsen | Williams - Renault | Report |
| French Grand Prix | 9 July | Paul Ricard | Alain Prost | Maurício Gugelmin | Alain Prost | McLaren - Honda | Report |
| British Grand Prix | 16 July | Silverstone | Ayrton Senna | Nigel Mansell | Alain Prost | McLaren - Honda | Report |
| German Grand Prix | 30 July | Hockenheimring | Ayrton Senna | Ayrton Senna | Ayrton Senna | McLaren - Honda | Report |
| Hungarian Grand Prix | 13 August | Hungaroring | Riccardo Patrese | Nigel Mansell | Nigel Mansell | Ferrari | Report |
| Belgian Grand Prix | 27 August | Spa-Francorchamps | Ayrton Senna | Alain Prost | Ayrton Senna | McLaren - Honda | Report |
| Italian Grand Prix | 10 September | Monza | Ayrton Senna | Alain Prost | Alain Prost | McLaren - Honda | Report |
| Portuguese Grand Prix | 24 September | Estoril | Ayrton Senna | Gerhard Berger | Gerhard Berger | Ferrari | Report |
| Spanish Grand Prix | 1 October | Jerez | Ayrton Senna | Ayrton Senna | Ayrton Senna | McLaren - Honda | Report |
| Japanese Grand Prix | 22 October | Suzuka | Ayrton Senna | Alain Prost | Alessandro Nannini | Benetton - Ford | Report |
| Australian Grand Prix | 5 November | Adelaide | Ayrton Senna | Satoru Nakajima | Thierry Boutsen | Williams - Renault | Report |
Question:
On what date did Ayrton Senna win at Imola?
Answer:
23 April