"peak figure" is correct and usable in written English.
You can use it to refer to the highest statistic or number at a certain point in time. For example, "The peak figure for the stock market last week was 32,425 points."
There are currently 154 detainees at Guantánamo, down from a peak figure of nearly 800.
A superconducting material typically causes a sharp characteristic peak (figure 1c) around the transition temperature.
Last year, when the Open concluded on Monday because of severe weather disruption, that peak figure on the BBC reached 4.7m.
This was the highest five-minute peak figure for any programme on any channel since England v Portual in Euro 2004.
On 8 December, 410 elective operations were cancelled – the single worst day so far this winter and 100 operations more than last winter's peak figure.
Currently, there are 112 children in immigration detention in Australia, about one-20th of the peak figure of 1,992 in July 2013.
The proposed ADC has been implemented in a 14 nm SOI FinFET technology and achieved a peak Figure of Merit (FoM) of 1.07 fJ/Conversion-step with simulation results.
Burns reflected that he was briefed to expect a further decline of 2% during 2010 when he started, so the turnaround has allowed C4 to restore the annual programme budget to £550m, below its peak figure but respectable.
It is the second highest for any 12 month period, only slightly lower than the peak figure of 320,000 recorded in the year ending June 2005.
The peak figure on this index was also around 45% in 2005, but this is an estimate, with the "true" level of volunteering being somewhere in the 44 46% range.
Gandhi's legal earnings reached a peak figure of £5,000 a year, but he had little interest in moneymaking, and his savings were often sunk in his public activities.
