Hyundai and Kia have a well protected domestic market, so they sell large numbers of cars at home. They also realised they need plants closer to the markets they sell in so in 1996 Hyundai's first overseas plant was opened in India. Other facilities were added and in 2009, Hyundai's overseas production passed the 50% of total volume. In 2016 it passed 70%.
Kia's first offshore plant was in China in 2002 but has been slower than Hyundai in developing production elsewhere. It has just reached the 50/50 split between domestic and overseas production volume in 2016. It's new Mexico plant will increase the overseas share in 2017.
The chart on the left is Hyundai and Kia is on the right.
Picture source: Netcarshow
Data source: Hyundai-Kia.
Text source: RayCee.