This term is credited to Luis Bush, International Director of the AD2000 International Office (closed in 2001). Bush wrote,

The core of the unreached people of our world live in a rectangular-shaped window! Often called "The Resistant Belt," the window extends from West Africa to East Asia, from ten degrees north to forty degrees north of the equator. If we are serious about providing a valid opportunity for every person to experience the truth and saving power of Jesus Christ, we cannot ignore the compelling reality of The 10/40 Window regions and its billions of impoverished souls.

According to the Status of Global Evangelization (SGE), a model that describes the progress of the Gospel among the peoples of the world, over half of the world's population (about 3.5 billion people) belong to unreached people groups where less than 2% of the population are Evangelical Christians. Amazingly, over two-thirds of these unreached peoples (about 2.3 billion people) live in countries that belong to the 10/40 Window.

Patrick Johnstone and Jason Mandryk are the authors of a book titled, Operation World. According to the statistics available in the 2001 edition of the book, and presented on the WorldVue CDROM from Global Mapping International, we learn some interesting facts about who lives in the 10/40 Window.

Poverty: 21 of the 48 poorest countries of the world

• GNP per person is $500 or less
• 77% of the poorest people (1.6 billion people)
• 7% of evangelical missionaries are working with this group

Lost: 31 of the 52 least evangelized countries of the world

• 95% of the least evangelized people (3.1 billion people)
• 10% of evangelical missionaries are working with this group

Hopeless: 11 of the 15 least evangelized, poorest countries of the world

• 98% of the least evangelized, poorest people (1.4 billion people)
• 4% of evangelical missionaries are working with this group

The Countries

There are 59 countries that lie at least partially within the 10/40 Window. Following is a complete list: