The figure below shows the pattern of filings over the last 24 months for the EB-5 (immigrant investor) program run by USCIS. Most of the investors are from China.
The top line shows the number of initial filings (Form I-526) per quarter; this is for the temporary resident card that comes with a $500,000 investment in an USCIS-designated (but not guaranteed) project. The lower line indicates the number of follow-on filings (Form I-829), in which the alien investor seeks to convert the temporary (two-year) permit into a permanent green card.
Source: USCIS statistics as reported by the Lucid Professional Writing blog.
I suspect that the fall-off has been caused by the continuing controversies that dog the program; the fact that the visa limit has been reached for Chinese, if not for other aliens; and perhaps by the reported efforts of the Chinese government to rein in the export of capital, for EB-5 and other purposes. The Obama administration has vigorously promoted the program.