how to calculate number of times key occur in json object or array in js : [{"StateID":"42","State_name":"Badakhshan","CountryID":"1"},{"StateID":"43","State_name":"Badgis","CountryID":"1"},{"StateID":"44","State_name":"Baglan","CountryID":"1"},{"StateID":"45","State_name":"Balkh","CountryID":"1"},{"StateID":"46","State_name":"Bamiyan","CountryID":"1"},{"StateID":"47","State_name":"Farah","CountryID":"1"},{"StateID":"48","State_name":"Faryab","CountryID":"1"},{"StateID":"49","State_name":"Gawr","CountryID":"1"},{"StateID":"50","State_name":"Gazni","CountryID":"1"},{"StateID":"51","State_name":"Herat","CountryID":"1"},{"StateID":"52","State_name":"Hilmand","CountryID":"1"},{"StateID":"53","State_name":"Jawzjan","CountryID":"1"},{"StateID":"54","State_name":"Kabul","CountryID":"1"},{"StateID":"55","State_name":"Kapisa","CountryID":"1"},{"StateID":"56","State_name":"Khawst","CountryID":"1"},{"StateID":"57","State_name":"Kunar","CountryID":"1"},{"StateID":"58","State_name":"Lagman","CountryID":"1"},{"StateID":"59","State_name":"Lawghar","CountryID":"1"},{"StateID":"60","State_name":"Nangarhar","CountryID":"1"},{"StateID":"61","State_name":"Nimruz","CountryID":"1"},{"StateID":"62","State_name":"Nuristan","CountryID":"1"},{"StateID":"63","State_name":"Paktika","CountryID":"1"},{"StateID":"64","State_name":"Paktiya","CountryID":"1"},{"StateID":"65","State_name":"Parwan","CountryID":"1"},{"StateID":"66","State_name":"Qandahar","CountryID":"1"},{"StateID":"67","State_name":"Qunduz","CountryID":"1"},{"StateID":"68","State_name":"Samangan","CountryID":"1"},{"StateID":"69","State_name":"Sar-e Pul","CountryID":"1"},{"StateID":"70","State_name":"Takhar","CountryID":"1"},{"StateID":"71","State_name":"Uruzgan","CountryID":"1"},{"StateID":"72","State_name":"Wardag","CountryID":"1"},{"StateID":"73","State_name":"Zabul","CountryID":"1"}]


this is my json object ,i want to calculate how many times key 'StateID' occurred in json object