The phrase "seems to be decreasing" is grammatically correct and can be used in written English.
It is often used to indicate that something is appearing to decrease, but it is not confirmed or definite. Example: According to recent studies, the population of polar bears seems to be decreasing due to the effects of climate change.
The number of protesters seems to be decreasing, but those engaged seem more determined.
If my own observations are anything to go by, availability of sickness bags on board aircraft seems to be decreasing.
This year's yet-to-be published Brits Abroad report by the Institute for Public Policy Research will show most Britons now emigrating are highly skilled, although the net loss of such workers seems to be decreasing.
But according to Andrew Odlyzko, a computer scientist at the University of Minnesota who specialises in analysing historical trends in networking, the actual rate of traffic growth is much lower than this and seems to be decreasing, not increasing.
"In Japan, the scholastic ability of people is not so high right now, and it seems to be decreasing, so I worry about the future of our country," said the teenager, who puts on a sober navy blue uniform and lugs a heavy book bag back and forth to his central Tokyo junior high school each day, including many Saturdays.
Although mortality due to injuries seems to be decreasing, high levels of interpersonal violence and accidents persist.
Moreover, the efficiency of PEG alone in solution, seems to be decreased when the deposit grows.
Degradation seems to be decreased when whole body were extracted and maintained at low temperature or the source of enzymes (abdomen) was removed (Fig. 12).
IL-17 expression is increased in the skin of acute AD patients [42], [43], while it seems to be decreased in chronic AD patients [44], [45].
Actually, the affected larval defence seems to be decreased by the exposures.
The CD154/CD40 ligand pair also seems to be decreased with ageing.
