It’s still up in the air whether the African Union can keep its promise to deliver a continental passport by the end of the year. The travel document would allow visa-free travel between the Union’s 55 member countries.

The potential economic impact is huge. Recently-released data show that intra-African travel continues to lag the world. The continent’s 1.2 billion people made far fewer intra-continental trips—in total, and per person—than Europeans, Asians and Americans.

In addition, as Europeans and Asians increasingly travelled to nearby countries, in recent years, African figures remained mostly the same.

Globally, intra-continental travel was a far more common practice than inter-continental travel. The amount, however, differs drastically from region to region. Sixty-five trips in Europe crossed into another European country for every 100 Europeans in 2016. Just four trips for every 100 Africans were to other African countries.

The data account for international travel by air, land and water transportations from 2011 to 2016. Ettore Recchi, the lead researcher behind the project, attributed the ease of traveling in certain regions to three factors:

Geographic proximity. Clusters of countries that occupy small areas—like in Europe—make it easier to take international trips. Economic prosperity. People with disposable income and places with a growing middle class—like Asia—are able to make more trips because they have the money to do so. Political integration. When political and administrative barriers to travel are removed—like in the European Union—it makes citizens more mobile.

Africa lagged behind on all these dimensions, according to Recchi.

Africa has been making improvements on political integration within the continent in recent years. Nigeria just announced that Africans traveling to the country do not need to apply for a visa beforehand. That means all Africans can now travel without a pre-trip visa to at least 53% of Africa’s countries. That’s up from 45% four years ago. US nationals can travel to 65% of African countries visa-free.

In 2016, the African Union promised to deliver a continental passport to “help realize the dream of visa-free travel for African citizens within their own continent by 2020.” A number of prominent Africans, including some heads of state and diplomats, have been issued the passport. Through August 2019, 33 member states have signed the protocol to establish a pan-African economic body, the first step toward the free movement of people.