How many cover models were on the edition that featured Jennifer Pershing as the centerfold?
{'header': ['Date', 'Cover model', 'Centerfold model', 'Interview subject', '20 Questions', 'Pictorials'], 'page_title': '', 'page_id': '', 'types': ['text', 'text', 'text', 'text', 'text', 'text'], 'id': '1-1566852-10', 'section_title': '', 'caption': '', 'rows': [['1-09', 'Carmen Electra', 'Dasha Astafieva', 'Richard Branson', 'Marston and Cooper Hefner', 'Carmen Electra'], ['3-09', "Aubrey O'Day", 'Jennifer Pershing', 'Kenny Chesney', 'Flight of the Conchords', "Aubrey O'Day"], ['4-09', 'Seth Rogen , Hope Dworaczyk', 'Hope Dworaczyk', 'Seth Rogen', 'Amy Smart', 'International Playmates, Bettie Page'], ['5-09', 'Lisa Rinna', 'Crystal McCahill', 'Chuck Palahniuk', 'Zachary Quinto', 'Lisa Rinna , Women of Wall Street'], ['6-09', 'America Olivo', 'Candice Cassidy', 'Shia LaBeouf', 'Scott Boras', 'America Olivo, PMOY - Ida Ljungqvist'], ['9-09', 'Heidi Montag', 'Kimberly Phillips', 'Seth MacFarlane', 'Diane Kruger', 'Heidi Montag. Michelle More & Suzanne Stonebarger'], ['10-09', 'Kiera Gormley , Tuuli Shipster', 'Lindsey Gayle Evans', 'Woody Harrelson', 'Shawne Merriman', 'Girls of the ACC'], ['11-09', 'Marge Simpson or Alina Puscau', 'Kelley Thompson', 'Benicio del Toro', 'Tracy Morgan', 'Alina Puscau , Farrah Fawcett']], 'name': 'table_1566852_10'}