Transactions between Australia and the rest of the world in 2017 are shown below.

The Australian government sells 18 million Australian dollars worth of treasury securities to UK citizens.

Australian companies sell 30 million Australian dollars worth of iron in the UK.

Australian companies pay 5 million Australian dollars in dividends to investors abroad.

Australian citizens spend 35 million Australian dollars while touring the US.

Australian government sends 12 million Australian dollars in aid to Africa.

US citizens spend 8 million Australian dollars in tuition at Australian universities.

Australian central bank buys 4 million Australian dollars worth of gold.

Find the current account balance in terms of millions of Australian dollars.