Myanmar census data, released on 29th May 2015, has provided us with some insights
The results of the nationwide census conducted for the first time in 30 years between March and April 2014 was released on 29th May 2015, the last census conducted was in 1983.

There have been many accusation that the census data excludes some minorities, particularly people in western parts of the country, due to “ongoing communal tension and the demand of many to self-identify as Rohingya” as UNFPA described. The count is also being criticized for being based on a list of 135 ethnic groups which activists say is outdated and inaccurate.

There are about 415,000 white card people (people who are currently living in the country but do not have a legal citizenship status) that report to respective movement officials however they will go through proper checks on their eligibility of citizenship.
The Ministry of Immigration and Population reveals that the total population in Myanmar is 51.5 million which takes into account of an estimated 1.2 million who did not formally register in Rakhine, Kachin and Kayin states. The male population comprised 24.82 million, representing 48.2% of the population and female comprised of 26.61 million; 51.8% of the total population. The figure contributes to 8.4% of the estimated total population in ASEAN region. Population density is high with 716 people per square km in Yangon region and 13 people per square km in Chin State, Western Burma.

It is also worth noticing that while birth rates are declining, there is a steady increase in young working age population. Current data reveals that the significant population; that is 67% is of working age (15-64) which means government need to accelerate the education reform to be able to fully benefit from qualified human resource before it enters into aging population.

The full census report can be found here: http://countryoffice.unfpa.org/myanmar/2015/05/25/12157/myanmar_census_2...