"As at / as on"

[kinfai]

Hi,

If I need to express the quantity of something up to a certain date, should I write

"As at 5 May 2005, the number of reported traffic accidents is . . ." or

"As on 5 May 2005, the number of reported traffic accidents is . . ."?

Or both are wrong?

Appreciate if someone could advise me.

[Pete]

Hi,

If I need to express the quantity of something up to a certain date, should I write

"As at 5 May 2005, the number of reported traffic accidents is . . ." or

"As on 5 May 2005, the number of reported traffic accidents is . . ."?

Or both are wrong?

Appreciate if someone could advise me.
The phrase that sounds natural to me is:

- As of 5 May 2005 the number of …

[kinfai]

Thanks a lot.

Actually I saw "... as at 6 May 2005 ..." in government documents and I wondered if it sounded natural.