'has significantly increased' is a correct and usable phrase in written English. You can use this phrase when you want to indicate that a quantity or value has drastically increased. For example, "In the last few years, the customer base of the company has significantly increased.".
As fashion weeks mushroom across Iran, the need for more models has significantly increased.
The government fails to tell you that flooding has significantly increased.
The Police Department has significantly increased its commitment to counterterrorism work.
"Loews has significantly increased and diversified its sources of cash flow".
It has significantly increased investments in basic research.
"The teen element has significantly increased over the last few years, and their behaviour has sadly deteriorated," wrote one.
Professional football, like other sports, has significantly increased security at stadiums since the terrorist attacks of Sept. 11.
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Ha Thuy Vy
MA of Applied Linguistic, Maquarie University, Australia