Though it is in the nature of migrant got-aways to be essentially unknown, decent estimates can be obtained. Some got-aways are observed by agents crossing the border but are not apprehended. Others are detected by cameras and other detection equipment. Still others are part of larger groups only some of whom apprehended.
The got-aways estimate for this fiscal year so far is that about 194,000 migrants have snuck across the border detected but not apprehended. That includes 62.000 in the El Paso sector and 54,000 in the Tucson sector. (Tucson was the busiest sector for apprehensions [373,220] and El Paso, the second busiest at 180,723.)
So far during the Biden tenure, a total of more than 1.8 million known got-aways have been estimated. More to come, of course.
For more, see Breitbart News.