The phrase "a relative decline" is correct and usable in written English.
It can be used to describe a decrease in something when compared to another reference point or over a specific period.
Example: "The company experienced a relative decline in sales compared to the previous quarter."
Alternatives: "a comparative decrease" or "a proportional drop."
A relative decline in power also does not mean that the United States will not remain powerful.
While there has been a relative decline in drug use among the young, "we cannot afford to sit idly by," Mr. Putin said.
Liège is already suffering a relative decline in business, partly because of a decision by TNT to shift more of its European traffic on to roads.
Although railroad transportation, as elsewhere in the United States, has suffered a relative decline in Alabama, bus, truck, and airline traffic have increased in the state.
Jens Ludwig, of the University of Chicago, argues that countries that took to the new drugs saw a relative decline in suicides.
A relative decline in the state's manufacturing occurred between the mid-1960s and the mid-1980s, and Pennsylvania came to be identified as part of a "rust belt" in which former industrial economies fell victim to strong competition from overseas.
The trend was to add more and more of the first and third arms, while the second, though retaining its high social prestige, underwent a relative decline in numbers and importance.
A high intensity tobacco control campaign would lead to a 2.5% relative decline in smoking rates by 2015 and prevent about 1 080 000 smoking attributable deaths by 2050.
After a brief crisis during World War I and recovery afterwards, a long relative decline ensued, with two prominent exceptions.
Instead, California is in a slow relative decline because it allocates its public resources badly.
That should have meant a smaller relative decline in the price of inefficient used cars.
