A portfolio is worth $90 million. The RTD400 index is thought to closely mimic the portfolio has a current value of 900. To protect against a market downturn, the managers of the portfolio decide to engage in a portfolio insurance strategy. The reference option strategy would be to buy 1,000 put options (100 times the index) on the RTD400 index with a strike price of 870. This option position would have the characteristics S0 = $90 million, K=$87 million, T=.5, r=.05, =.25, and q=.03. What is the delta of the reference option position?