Hebrew Publishing

Prof. Shaul Stampfer, "What Did 'Knowing Hebrew' Mean in Eastern Europe?" in Lewis Glinert ed., Hebrew in Ashkenaz: A Language in Exile, p. 137:

In the twentieth century, literary creativity in Hebrew and publication in Hebrew continually lagged behind that of Yiddish in Poland. Of about a thousand Jewish books published in Poland in 1928, about a quarter were in Hebrew. Two years later, the share of Hebrew books was under 20 percent. This does not necessarily mean that there was a decline in the readership of Hebrew. The drop might well be the product of increased imports from Eretz-Israel. What it does mean is that patterns of Jewish publishing were becoming more and more like those of other nations in that vernaculars took the lead.

Which makes me wonder, what percentage of Jewish books in the US is published in Hebrew?