According to the estimates of the International Monetary Fund (IMF), the gross domestic product (GDP) of 186 countries will increase by $2.8 trillion – nearly 4 percent – in 2016, reaching a total of $75 trillion.

The highest national income increase is expected to be in China, which worries global economies with its growth rates and currency devaluations. China's national income will increase by $869 billion to $12.3 trillion this year, compared to 2015. The United States will follow, with an increase of $729 billion according to the IMF, which is followed by India with a $202 billion increase. The U.K.'s GDP will increase by $189 billion, while Germany's GDP is forecasted to rise by $101 billion.

The national incomes of 16 countries are expected to decrease this year with the highest drop expected in Brazil – an estimated $126 billion – followed by Russia with $56 billion and Kazakhstan by $21 billion. The total economic contraction in these 16 countries will amount to $238.3 billion.

The IMF's 2016 estimates for the GDP seem not to have changed, as the U.S. still has the highest national income at $18.7 trillion, followed by China with $12.3 trillion. Japan comes in third with $4.2 trillion, followed by Germany with $3.5 trillion and the U.K. with $3.1 trillion.

The total national income of the top five countries; the U.S., China, Japan, Germany and the U.K., is expected to reach $41.7 trillion in 2016, which amounts to 55 percent of the world's national income. Despite a $1 million increase from last year, the southern Pacific island nation of Tuvalu has the lowest national income in the world at $35 million.  Turkey is listed in 18th with an expected GDP of roughly $721 billion in 2016.