A HDI below 0.5 is considered to represent "low development". All 22 countries in that category are located in <answer>Africa</answer>. The highest-scoring Sub-Saharan countries, Gabon and South <answer>Africa</answer>, are ranked 119th and 121st, respectively. Nine countries departed from this category this year and joined the "medium development" group.
On which continent are all 22 of the low development countries located?
Africa