截至 / 自…以来: as of / since
介词 / prepositions
Tone colorsā tone 1á tone 2ǎ tone 3à tone 4a neutral
Two written time markers, everywhere in statistics and the press:
• 截至 ("as of, up to"): the cut-off date of a figure: 截至去年底 (as of the end of last year).
• 自…以来 ("since…"): a period starting at some point and lasting until now: 自改革开放以来 (since reform and opening-up).
Don't confuse 截至 (cut-off, followed by a date) with 截止 (verb "to close": 报名已截止).
Examples
截至去年年底，中国的高铁里程已超过四万公里。
Jiézhì qùnián niándǐ, Zhōngguó de gāotiě lǐchéng yǐ chāoguò sì wàn gōnglǐ.As of the end of last year, China's high-speed rail network exceeded 40,000 km.
自加入世贸组织以来，中国的对外贸易迅速增长。
Zì jiārù Shìmào Zǔzhī yǐlái, Zhōngguó de duìwài màoyì xùnsù zēngzhǎng.Since joining the WTO, China's foreign trade has grown rapidly.
报名已经截止了，下次请早点儿。
Bàomíng yǐjīng jiézhǐ le, xià cì qǐng zǎo diǎnr.Registration has closed: next time, please sign up earlier.
Common mistakes
✗ 截止去年年底 (in a statistic) → ✓ 截至去年年底.
✗ 自…以后 for a period up to now → ✓ 自…以来.
✓ 自从…以来 is also fine.