Table:
text: Greg Norman
PGA Tour wins (20)
PGA Tour wins (20)
Date_ Tournament Winning_score Margin_of_victory Runners_up
4 Mar 1990 Doral-Ryder Open –15 (68-73-70-62=273) Playoff Tim Simpson , Mark Calcavecchia , Paul Azinger
13 May 1990 Memorial Tournament Even (73-74-69=216) 1 stroke Payne Stewart
13 Sep 1992 Canadian Open –8 (73-66-71-70=280) Playoff Bruce Lietzke
7 Mar 1993 Doral-Ryder Open –23 (65-68-62-70=265) 4 strokes Paul Azinger , Mark McCumber
18 Jul 1993 The Open Championship –13 (66-68-69-64=267) 2 strokes Nick Faldo
27 Mar 1994 The Players Championship –24 (63-67-67-67=264) 4 strokes Fuzzy Zoeller
4 Jun 1995 Memorial Tournament –19 (66-70-67-66=269) 4 strokes Mark Calcavecchia , David Duval , Steve Elkington
25 Jun 1995 Canon Greater Hartford Open –13 (67-64-65-71=267) 2 strokes Dave Stockton , Kirk Triplett , Grant Waite

Question: What date was the Memorial Tournament held when Payne Stewart was runner-up in Greg Norman's PGA Tour wins (20)?