Last year, more than half a billion passengers took public rail transit, including metro, tramway and cable car in Istanbul, which has a population of nearly 15 million. Based on Istanbul Ulaşım A.Ş. statistics, the metro is the most popular public transit among Istanbulites. Compared to 2014 statistics, the number of passengers taking rail public transit increased by 75 million, breaking an all time record. Around 400 million passengers took the metro on the city's five main metro lines in 2015. Among them, the M1 Yenikapı - Atatürk Airport / Kirazlı metro line was the busiest with 143 million passengers. Almost 163 million passengers used the tramway in the same period. The T1 Bağcılar - Kabataş line is the most popular tramway line, carrying 120 million passengers. The number of passengers decreases in summer months and increases in winter. New metro lines are also on the Istanbul Metropolitan Municipality's agenda. The Ataköy-İkitelli metro line on the European side and the Dudullu-Bostancı metro line on the Anatolian side will be constructed.