[Grammar] Since 1946 the population has doubled.

[sitifan]

1. Since 1946 the population has doubled. (quoted from an English textbook published by the National Institute for Compilation and Translation in Taiwan)
2. Compared with 1946, the population has doubled. (quoted from English Grammar, by Yan Sihua)

Mr. Yan Sihua, a Taiwanese teacher of English, says #1 is not acceptable. Only #2 is correct. Do native speakers agree with what he says?

 

[GoesStation]

Not I. If this one is at all representative, you can disregard Yan's opinions.

 

[tedmc]

Did she say why #1 is not acceptable?

Is there any difference whether you compare the population increase of the period from 1946 up to the present and between that of the year 1946 with the present?