The phrase "has continually increased" is grammatically correct and can be used in written English.
Example: The company's profits have continually increased over the past five years due to their successful marketing strategies.
Public and federal scrutiny of the police, since the shooting of Michael Brown, in Ferguson, Missouri, in the summer of 2014, has continually increased, too.
It has continually increased its annual revenue, to around $1.9 billion in 2006, has always been profitable and has never borrowed a penny.
It has continually increased its annual spending to help offset the costs of keeping U.S. troops there.
Like its rivals, JPMorgan has continually increased the amount released from its reserves with $1.7 billion released in the third quarter and $2.4 billion in the second.
As a result the debt/GDP has continually increased.
During this time, the productivity of American workers has continually increased — but only those at the top pocketed the rewards for everyone else's hard work.
Since 1998, undergraduate and graduate student majors have continually increased, exceeding 160 students for the first time this year.
In contrast to the east's slow, post-1990 recovery, farmers in western Europe have continually increased their annual productivity so that there is now a significant gap in output between east and west.
Contrary to observations of decreasing rates in Western nations for the past 2 decades, age-adjusted rates of hip fracture in the general population in Japan have continually increased.
Another survey, from Public Policy Polling, pegged Mr. Gingrich's lead at 9 points — but found that it had continually increased as the poll was in the field, with Mr. Gingrich ahead by 14 points based on interviews conducted after the Thursday night debate.
