North Dakota's "Legacy Fund" > $535 Million

Link here to the Dickinson Press/Inside Climate News.

The "Legacy Fund":

in existence since August, 2011 (thereabouts); 13 months old according to DP/ICNvoters approved in 2010
accrues from 30 percent of the state's oil tax collections
cannot be spent until 2017
requires two-thirds of Legislature to approve spending
first deposit: September, 2011
most recent deposit: $45 million; growing faster than anticipated

Back-of-the-envelope calculations: 2017 --> 60 months from now x $50 million/month --> $3 billion. My understanding is that the money is invested in money market accounts.

If $45 million represents 30 percent for the most recent month, what was the total? $150 million.