The club's latest accounts show that their debt now stands at around £34million, which includes the £15million mortgage on Pride Park.
The net loss for the year ending June 2012 was £7.9million, slightly up on the £7.7million for the previous 12 months.
The club's turnover was £17.3million, down from £18.1million the year before, while operating costs were reduced from £17.6million to £17.3million.
Despite the figures, Derby remain confident they are on the right course and insist the ownership group will continue to bankroll the club because they believe in the work being done by manager Nigel Clough.
Chief executive Rush said: "Although the figures relate to a time prior to my arrival at the club, they do offer evidence of one of the key factors that attracted me to Derby County.
"We have a strong ownership group who continue to be the single biggest source of finance. The simple truth is that somebody has to cover our working capital needs, as well as make continued investments in our squad and wider infrastructure.
"The ownership group's strength offers the club that much-needed financial stability. We aim to be both successful and sustainable. Increasingly, clubs won't be able to gamble their futures as they have in the past, and this can only be good for the long-term health of the game.
"I and the rest of the board aim for Derby County to be successful and challenging for promotion, and we will do this the right way, through hard work and continued improvement.
"This stability and ethos runs right through the club and this year we have all seen further development on the field. Nigel Clough has created a young and exciting team that people are talking about in a very positive and complementary way."