"the swiftest increase" is a correct and usable phrase in written English.
For example, you could use it in a sentence like, "The industry experienced the swiftest increase in sales during the summer months."
Economists said the two moves could somewhat slow the swift increase in bank lending that has caused a steep rise in China's money supply and has raised fears that Chinese banks may be creating another wave of bad loans.
The swift increase in enrollment has long made supporters of the law anxious.
With the swift increase in the number of older persons, an increasing demand for long-term care facilities has arisen.
He promised to slow the swift increases in the money supply and in bank lending that have fueled the recent acceleration in growth, but said that a loosening of the peg of China's currency to the dollar would have to wait for banking reforms.
The early and swift increase in fluorescence intensity indicated that oligomers formed quickly, and the later, coincident increase in ThT and FlAsH fluorescence intensity as well as FRET suggested that oligomers were on-pathway for fibril formation, and that fibrils formed more slowly than smaller oligomers.
The idea of treating a displaced femoral neck fracture with hemiarthroplasty, as an alternative to internal fixation, won increasingly greater acceptance in the country from the late 1990s with a swift increase until 2005, after which the increase has leveled off (Rogmark et al. 2010).
India's government is now bracing the country for a swift increase in the price of diesel fuel and other imported necessities priced in dollars.
The result was a swift increase in larger planes with improved radial engines and a shift from biplanes to trimotor monoplane transports marketed by a subsidiary of Ford and by the European builder, Anthony Fokker, who had set up shop in the United States.
We find a swift increase of the viral density as a function of the time of initiation of the therapy measured when the therapy is stopped.
On 3 occasions, the area of low uptake had decreased from one PET scan to the next (Table), when a swift increase in uptake then ensued.
