What is the similar about negative growth rate and zero growth rate?

Zero growth rate represents that a country's population is not growing, that means that the total number of births during a year were equal to the total number of deaths during that year, e.g. Iceland, Germany, Portugal, and Poland.

A negative growth rate means that more people died in the country than the number of people born during that year, e.g. Italy, Japan, Russia, and Ukraine.

The similarities between countries that experience either a zero growth rate or a negative growth rate is that in the long run the economy will face extremely serious problems. Several countries are starting to face problems related to an increase in the number of retirees and a decrease in the total work force. As the number of total working adults decreases, the government's revenue decreases, but since the number of retirees increases, the government spending increases, creating a huge budget deficit.