BEIJING -- China's banking system saw improved concentration with the asset proportion of five large state-owned banks in a reasonable range, the country's banking and insurance regulator said Monday.

The total asset of the five state-owned banks stood at 105 trillion yuan (about $15.17 trillion), accounting for 37 percent of all banking financial institutions, the China Banking and Insurance Regulatory Commission (CBIRC) said on its website.

The five state-owned comprehensive commercial banks include the Bank of China, Industrial and Commercial Bank of China, Agricultural Bank of China, China Construction Bank and Bank of Communications.

By the end of 2018, China had 4,588 banking financial institutions covering over 20 types of banks, CBIRC data showed.

Of the sector's total, the balance of deposits and loans of the five state-owned banks made up 44 percent and 38 percent, respectively.

Compared with the United States and major economies in Europe, China's domestic banking system posted a lower concentration, the CBIRC said.

With mixed-ownership reform promoted in recent years, the number of financial institutions controlled by private capital has exceeded 3,000. Private capital accounts for 40 percent, 50 percent and 80 percent in the capital stock of joint-equity banks, city commercial banks and rural cooperative banks, respectively.

China would continue to accelerate financial supply-side structural reform and optimize the banking service system, said the CBIRC.