The ISS is arguably the most expensive single item ever constructed.[265] As of 2010 the cost is estimated to be $150 billion. It includes NASA’s budget of $58.7 billion for the station from 1985 to 2015 ($72.4 billion in 2010), Russia’s $12 billion ISS budget, Europe’s $5 billion, Japan’s $5 billion, Canada’s $2 billion, and the cost of 36 shuttle flights to build the station; estimated at $1.4 billion each, or $50.4 billion total. Assuming 20,000 person-days of use from 2000 to 2015 by two to six-person crews, each person-day would cost $7.5 million, less than half the inflation adjusted $19.6 million ($5.5 million before inflation) per person-day of Skylab.[266]