The capital of Ukraine is the City of Kyiv - Article 20 of  Ukrainian Constitution  

Article 20 - The capital of Ukraine is the City of Kyiv - http://www.rada.gov.ua/const/conengl.htm#r1

Saying that google finds more for Kiev that Kyiv and it's the main reason to igore change to Wikipedia articles consering Kyiv - makes no sense. In your logic we should next change ukrainian constitution due to google search result. Of course in USSR Kyiv in every foreign press was spelled as Kiev. As a resulat it caused a habit to spell name of the capital of Ukraine in wrong way even up to day, but we are not living in USSR anymore. We are living in independent Ukraine and the capital of this country is Kyiv.