Facebook now has 100 million users across Africa, the company announced on Monday.

This figure is half of all the Internet users in Africa, which sits at 200 million people. More than 80% of Facebook users are accessing the site from a mobile phone, showing high-growth countries are more connected than ever before.

Facebook engineers started tweaking the company’s Android app earlier this year after a trip to Africa revealed that the app was loading very slow, and the lack of memory on the devices resulted in constant crashes. The team members also burned their monthly data plans in 40 minutes. The team reduced the app’s download size by 65%, and decreased start times by more than 50% in the six months following the trip.

It looks like their work paid off. The huge numbers of people accessing the Internet on mobile devices in high-growth areas comes as many use their mobile phones not just to communicate, but as a lifeline for banking, employment and other necessary services. Keeping this in mind, Facebook and advertising agencies are customizing features and campaigns based on local insights, data speeds and available devices.

Rob Norman, chief digital officer of media buying firm Global Group M, said in a blog post on Monday that services, such as Facebook, need to deliver maximum use for the smallest amount of data.

“In Africa, we are seeing explosive growth and incredible momentum across the region. At the same time, when you look at the staggering cost of connectivity in many countries, mobile services need to deliver maximum utility on the biggest range of devices and consume the smallest amount of data, which is exactly what Facebook provides,” he wrote.

In June this year, Facebook was behind a major initiative to bring Internet to Zambia in Southern Africa. Internet.org gave locals access to basic apps such as health and employment services, Wikipedia, Facebook, Google Search, a women’s rights and a weather app.

“Everything Facebook has done has been about giving all people around the world the power to connect,” Zuckerberg said in a statement at the time of the launch of internet.org in 2013.“There are huge barriers in developing countries to connecting and joining the knowledge economy. Internet.org brings together a global partnership that will work to overcome these challenges, including making internet access available to those who cannot currently afford it.”

These newly announced figures seem to prove Zuckerberg’s global access mission is getting closer to success.