美国 F4移民进度，怎么看？

Processing Times1). Select a form type2). Select a form sub-type3). Select an officeGet Results Reset

USCIS National Goal - 5.0 Month(s)

USCIS National Average - 20.9 Month(s)

California Service Center - 47.3 Month(s)
Effective as of: 十二月 31, 2013
View national volumes and trends for all applications
我通过美国的[url]https://egov.uscis.gov/cris/Dashboard/ProcTimes.do 网站，输入WAC号码，进行查询，是上面这个结果，看不懂是什么意思？请班主看看！