Six of the Midlands' eight Premier League and Championship clubs in 2012/13 posted a drop in revenue.
Only Aston Villa and West Bromwich Albion saw turnover in 2013 increase on the previous year, by two per cent to £81.7 million for Villa and by five per cent to £69.7 million for The Baggies.
Aston Villa, which was put up for sale last month, was also placed in 10th position in the overall ranking of English clubs by turnover in 2012/13.
Overall revenue in the Premier League topped £2.5 billion for the first time, boosted by a 21 per cent increase in commercial revenue.
The data is contained in the latest Annual Review of Football Finance, published by the Sports Business Group at financial services firm Deloitte.
Of the six clubs, Wolverhampton Wanderers posted the largest fall in turnover, by 47 per cent to £32.1 million in 2012/13, as a result of being relegated from the Premier League in 2011/12.
Birmingham City also suffered a heavy fall in sales, down 37 per cent to £24.7 million, which was attributed to a reduction in parachute payments following its relegation from the Premier League in 2010/11 and no income from the Europa League after its appearance in the 2011/12 competition.
The other Midland clubs posting a drop in turnover were: Stoke City (£66.5 million, six per cent); Leicester City (19.6 million, eight per cent); Derby County (£15.4 million, 11 per cent) and Nottingham Forest (£14.4 million, two per cent).
During 2012/13, there were 15 clubs from the West and East Midlands playing in the top four tiers of English football which had combined revenue of more than £350 million.
This was equivalent to around 11 per cent of the total revenue of the circa £3.2 billion generated by the 92 Premier League and Championship clubs in English football.
Of the region's three Premier League clubs in 2012/13 - Aston Villa, Stoke City and West Bromwich Albion - only the latter recorded an operating profit, with £6.2 million.
Aston Villa's operating loss of £24 million was the second highest in the Premier League while accounts published earlier this year revealed Villa had made a four-year loss of £162m .
England's flagship top division had overall net debt of £2.5 billion in 2012/13, with almost £1.6 billion of that in the form of so-called 'soft loans' which do not incur interest.
Almost all of these loans were related to just four clubs - Chelsea (£984 million), Newcastle United (£266 million), Queens Park Rangers (£166 million) and Aston Villa (£72 million).