changes.

increased

rose, grew, went up, climbed

an increase

a rise, growth, a gain

increased quickly

jumped, leapt, surged, shot up

increased slowly

crept up, edged up, inched up

decreased

fell, dropped, declined, went down

a decrease

a fall, a drop, a decline

decreased quickly

plunged, plummeted, slumped, tumbled

decreased slowly

eased, slipped, edged down, tapered, tailed off

stayed the same

held steady, remained flat

stopped rising

levelled off, plateaued

went up and down

fluctuated, swung, varied

caused a rise in

pushed up, drove up, lifted

caused a fall in

pushed down, cut, curbed

increased spending on

put more into, stepped up

reduced spending on

spent less on, pared back

sharply

Abrupt, at a point in time. Answers WHEN. Implies the change was large

steeply

Severe gradient, over a stretch. Answers WHAT SHAPE. Implies the change was large

rapidly

Fast, over a stretch. Answers HOW FAST. Says nothing about size

gradually

Slow

steadily

At an even rate

curbed

Reduce, by an agent acting deliberately. The thing is held down, not removed

dwindled

Slow decline towards nothing. Use when the source says the thing is running out

spiked

Up then straight back down

shrank

For size or scale

dipped

Small and temporary

bottomed out

Fell, and the fall has now ended

levelled off

Stopped changing after a period of movement