A labour force's annual incomes are lognormally distributed. If the labour force is arranged in order of decreasing annual incomes and the top 10% earns 37% of the total annual incomes, what proportion of the total annual income does the bottom 10% earn?

Kindly help on this one. It looks simple until you start solving and you realise that there is no mean or variance!

Also take note that all the information is provided. There is nothing missing in this question,