Stay high = 居高不下 [jū gāo bù xià]
A cat sits on top of a utility pole and will not come down. Stay (居) high (高), not (不) down (下): 居高不下.
居高不下 (jū gāo bù xià) is a set phrase meaning “to remain high” or “to stay stubbornly high.” It is used for numbers that will not come down, such as prices, temperatures or unemployment. The cat on the pole is the literal picture.
In speech, 不 changes to a rising tone before a falling tone, so the phrase is pronounced jū gāo bú xià.
房价居高不下。 — Fángjià jū gāo bú xià. — Housing prices remain high.
气温居高不下。 — Qìwēn jū gāo bú xià. — Temperatures are staying high.