In 2013, Furl Co. sold 15 million units of chocolate bars, which represented 35% unit market share. As years passed, the total number of units sold for chocolate bars remained the same, but Furl Co. continued to increase its unit market share. In 2019, Furl Co.'s unit market share reached 40%.

Given that the total number of units sold in the market for chocolate bars remained the same, what range does the percentage change in number of units sold by Furl Co. from 2013 to 2019 correspond to in the options below? (rounded to the nearest whole number)