These mini-charts explain one of the biggest global demographic trends

There are basically two big demographic stories in the world right now: Populations in developed markets (and emerging Europe) are shrinking, while the populations in emerging and frontier markets are rapidly growing.

However, there are huge differences among emerging and frontier countries. Some face structural issues, while others struggle with huge youth unemployment issues, as a Credit Suisse research team led by Amlan Roy recently noted in a report.

Notably, there is no clear criteria defining emerging market versus frontier markets; frontiers are basically a subset of EMs. Generally speaking, countries designated as emerging markets are a bit more "developed" than frontiers, although that doesn't necessarily mean that they are richer.

We took a closer look at some of these countries, based on which regions they are in, using population pyramid charts from Credit Suisse's report that illustrate the age and sex breakdowns of each country's population in 1980 and in 2015. Check it out.

Frontier markets in Eastern Europe, which have slogged through social, political, and economic transformations since the fall of the Iron Curtain, are getting older, and the trend doesn't seem to be reversing anytime soon. Bulgaria, for example, has an extremely high old age dependency ratio of 30.42 older adults over 65 per every 100 working age adults aged 15-64.

The fertility rates in Croatia, Bulgaria, and Lithuania were estimated by Credit Suisse to all be around 1.5 children per woman in 2015-2020, lower than in 1980-1985. And although Credit Suisse projects these countries to see slight upticks to around 1.7-1.8 children per woman in the future, that's still lower than birth rates in the '80s, and still below the replacement rate of around 2.1 children per woman needed to halt a population decline.

The second and related big problem for eastern European countries is the brain drain resulting from disastrously high youth unemployment rates. Millennial-aged workers are leaving their home countries in droves, hoping to find better opportunities in developed European markets.

On the flip side, frontier African countries are on the younger side and have high birth rates. Nigeria and Kenya, for example, have average annual population growth rates of over 2%, double the world average. Moreover, Nigeria's birth rate is at 5.48 children per woman.

These countries are projected to continue seeing rapid population growth, with a very quickly expanding potential workforce in the years and decades to come.

However, frontier African nations face structural issues. According to Credit Suisse's report, African frontier markets lag behind other countries in terms of access to sanitation facilities and water sources, with only 29% of Nigeria's population and 30% of Kenya's having any access to sanitation.

Additionally, Credit Suisse's data shows that Nigeria is the only frontier economy on their list with primary school enrollment below 90%, with a rate of just 85%. Furthermore, only 50% of adults in Nigeria are literate.

Asian frontiers tend to have larger economies than frontiers in Europe as measured by absolute GDP level. However, they are much poorer than European and Middle Eastern frontiers in terms of GDP per capita. To put this in perspective, Bangladesh's GDP per capita is only about 2.5% that of Kuwait, which is the richest frontier country on Credit Suisse's list and has a GDP per capita level similar to France's.

The Asian frontiers have large populations: For example, Pakistan's population (188.92 million) is 65 times that of Lithuania's (2.88 million). Of course, a larger population doesn't automatically translate into more economic growth.

Notably, Bangladesh saw one of the largest increases in life expectancy from 1980 to 2015, which Credit Suisse suggests "may possibly be attributed to advances in micro-finance and female literacy rates."

The Middle Eastern frontier markets are on the richer side and they perform better in terms of secondary and tertiary education enrollment than frontiers in Asia and Africa. Additionally, the most urbanized frontier countries are in the Middle East.

Notably, Lebanon has the highest life expectancy at birth of all the frontier market countries on Credit Suisse's list at 80.3 years. By comparison, Nigeria's life expectancy is at only 53.7 years. "This is equivalent to a gap of a generation or nearly two in terms of average life expectancies," writes the Credit Suisse team.

However, labor force participation rate gender gaps are high in the Middle East. Lebanon and Oman's gender gaps are around 50 percentage points, while Kuwait's is at 36 points, according to data cited by Credit Suisse.

More from Business Insider:

http://uk.businessinsider.com/demographics-shift-first-time-in-human-history-2016-3

http://uk.businessinsider.com/animation-of-japans-demographic-headwinds-2016-3