I have noticed that there have been very few ILs sent by the USCIS for this month (as of now). Recently, the Interview Letters were being received (across all DOs) during the 2nd or 3rd week of the month, but for this month (April) there has been very very few ILs so far for all the District Offices. For instance in the Washington DO, the last IL was received 41 days back (for the cases that are being tracked). Any comment or idea why this might be happening?