The Asian Development Bank (ADB) announced on Tuesday that its private sector operations performed strongly in 2013, with more than $4.75 billion worth of investments in sectors such as clean energy, agriculture and health.

"The results show that our private sector operations are making a significant contribution to ADB's overall financial and developmental goals," Todd Freeland, the director General of the ADB's private sector operations, said in a press release.

The ADB approved a record number of private sector transactions last year that expanded its investments in core sector including renewable energy, clean water and financial services. The bank also continued to grow its activities in newer sectors such as agribusiness and health.

According to the ADB, its total investment portfolio in now more than $6.2 billion--more than double where it stood before the 2008 financial crisis.

"The growth in private sector operations is consistent with our belief that the private sector is vital to the development of inclusive and environmentally sustainable growth throughout Asia," Freeland said. "We expect to continue to expand our private sector operations significantly over the next 5 years in support of this objective," Freeland said.

The department's 2013 Development Effectiveness Report showed that the success rate for private sector transactions from 2011-2013 increased to 67 percent from 53 percent in the 2010-2012 period.