A record 29 managers in the top four English divisions were sacked in the first half of this season.
Brendan Rodgers, Tim Sherwood, Dick Advocaat and Jose Mourinho were replaced in the Premier League, while 10 Championship managers were fired.
The 29 dismissals across the 92 Football League clubs between 1 June and 31 December 2015 is the most ever at this stage of the season.
The highest number for a single season is 53, in the 2001-02 season.
"We must continue to shine a light on this issue," said League Managers' Association (LMA) chief executive Richard Bevan.
"With the hire-and-fire culture engrained within football, it's so difficult to survive for any meaningful length of time in order to learn your trade, learn from mistakes and experiences. Managers must cope with instant judgements and, often, success and failure are rarely that far apart."
The tally of 29 dismissals at this stage of the campaign is two more than the previous high set in the 2014-15 season.
A statement from the LMA said: "If the trend continues, we are on course to exceed the highest number of dismissals in one season over the past 10 years."
The managers dismissed so far this season had held their job for an average of only 1.58 years, and eight of the 29 were first-time managers.
Arsenal manager Arsene Wenger remains the longest-serving current manager at 19.26 years, with Exeter City boss Paul Tisdale in second place on 9.52 years.
"Professional football is the ultimate results-driven business, with owners, boards and supporters' expectation levels going up and up year on year," added Bevan.
"Boards need to take a step back and look at their league position compared to resources, squad, stadium capacity, attendances, and compare themselves with other similar clubs."