Lack of core titles in the market was another reason for the dull software sales. In the fiscal 2014 year, GameStop's software sales declined 11.3% year-over-year (y-o-y). GameStop's game sales through the buy-sell-trade model are highly correlated with new game sales, as the latter help replenish the company's inventory; pre-owned game sales have consistently been around 65% of new software sales for the last four years. However, in 2014, this figure improved to 77%. This indicates that a decline in software sales might significantly impact the Used Video Game Products segment. Trefis estimates the software revenue per square foot to increase to $368 by the end of 2021, and Used Video Game Product revenue per square foot to rise to $288 over the same period. In the above mentioned scenario, Software sales per square foot might drop to $250 by the end of our forecast period, whereas the used video game products revenue per square foot might drop to $240 over the same period.