Some trends I noticed from this view of the data at a cursory glance is that the mid-nineties seem to be a big boom for immigration into the United States from a greater variety of places compared to the other periods. Overall migration shrinks both in terms of absolute numbers and representation from different countries. The second piece of this trend might be explained by the dot-com bust and 9/11, a changed economic and political climate that seems to still be resonating today. Greater prosperity in many countries as the world stabilized after the end of the Cold War may have also reduced the incentive to move to the United States.
Less dramatic observations are the ready increase of people arriving from Mexico, China, and India, likely coinciding with the need for labor skills from those countries. There are also some countries, such as the Phillippines and Vietnam that provide a remarkably consistent and constant flow of migrants, likely due to certain visa programs, such as family reunification, that strictly manage immigration numbers.