Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Country | Area (km²) | Population (millions, 2011) | GDP (PPP) (USD, per capita) | GDP (nominal) (billions USD) | HDI (2011) |
| --- | --- | --- | --- | --- | --- |
| Algeria | 2,381,741 | 37.1 | 7200.0 | 183.4 | 0.698 (medium) |
| Libya | 1,759,540 | 6.7 | 14100.0 | 177.9 | 0.760 (high) |
| Mauritania | 1,025,520 | 3.4 | 2200.0 | 4 | 0.453 (low) |
| Morocco | 710 850 | 32.3 | 5100.0 | 103.8 | 0.582 (medium) |
| Tunisia | 163,610 | 10.7 | 9500.0 | 48.9 | 0.698 (high) |
Question:
What is the population in millions for 2011 where the GDP (nominal) (billions USD) is 4? 
Answer:
3.4