MOSCOW, June 30 (Reuters) - Growth in retail lending could reach 20% in Russia this year and the risk of overheating in the sector is real as people’s incomes are growing at a slower pace, Central Bank Governor Elvira Nabiullina said on Wednesday. Nabiullina said the central bank was looking closely at retail lending and mortgages to prevent bubbles from forming. (Reporting by Elena Fabrichnaya, Andrey Ostroukh and Alexander Marrow;) Our Standards: The Thomson Reuters Trust Principles.