At the beginning of 2007, an investor buys 2 shares at $100 each. At the beginning of 2008, he buys another 3 shares at $120 each. At the beginning of 2009, he sells 1 share at $110 each. At the beginning of 2010, he sells the remaining 4 shares at $130 each. The stock does not pay any dividend. Calculate the dollar-weighted rate of return.