what is the number of area where the county is marsabit?
{'header': ['Code', 'County', 'Former Province', 'Area (km 2 )', 'Population Census 2009', 'Capital'], 'page_title': '', 'section_title': '', 'caption': '', 'rows': [['10', 'Marsabit', 'Eastern', '66,923.1', '291166', 'Marsabit'], ['11', 'Isiolo', 'Eastern', '25,336.1', '143294', 'Isiolo'], ['12', 'Meru', 'Eastern', '6,930', '1356301', 'Meru'], ['13', 'Tharaka-Nithi', 'Eastern', '2,409.5', '365330', 'Chuka'], ['14', 'Embu', 'Eastern', '2,555.9', '516212', 'Embu'], ['15', 'Kitui', 'Eastern', '24,385.1', '1012709', 'Kitui'], ['16', 'Machakos', 'Eastern', '5,952.9', '1098584', 'Machakos'], ['17', 'Makueni', 'Eastern', '8,008.9', '884527', 'Wote']]}