Previously, I stated the following:
The graph below shows this correlation in the United States from 1970 to 2019. (I did not include 2020 in the graph due to the extraordinary temporary jump in the savings rate during the Pandemic Recession.)
Figure 6.3. Private Investment and Personal Savings by Fred Rowland is used under a CC BY-NC 4.0 License. Source: Federal Reserve Economic Data (FRED) (12/2020).
This correlation of investment to savings is also true in the rest of the world:
Figure 6.4. Household Savings Rates as a Percent of Disposable Income (in %) by Fred Rowland is used under a CC BY-NC 4.0 License. Source: OECD iLibrary data (11/24/2020).
From this, we see that one of the things a country can do to stimulate investment (and economic growth) is to encourage higher rates of savings among its citizens. The consequences of low rates of savings can be seen best in Sub-Saharan African countries. Many citizens in these countries are subsistence farmers and have almost no savings. As a result, there is not a large supply of loanable funds, which are essentially deposits in local banks. Since the supply is low, interest rates are high on loans, which curtails investment. Low ratios of capital equipment to labor result in low productivity of workers. Low productivity of workers results in workers being paid low wages. Low wages mean workers have low or non-existent savings. You can see how this is a vicious circle.