In uract wring to South Korea a Therapy-based mental health app, you first need to roughly estimate your market demand there. Your market research (country reports) yields the following statistics:

• Therapy mental health app users in China: 30M
• Therapy mental health app market share in China 7%
• Total adult population in Korea: 45M
• Smartphone ownership in Korea: 94%
• At least "somewhat interested" in mental health products in Korea: 30%
• Currently using any mindfulness or meditation apps in Korea: 4M

According to the Chain Ratio method, market demand estimate for South Korea could be:

45M 94% 30% = 12.7

45M

OAM

60M 7% = 4.2M