Immigration to the United Kingdom has risen sharply in recent years, and it's fueling the debate about Britain's looming "Brexit" vote on whether to leave the European Union.

Many supporters advocating a "leave" vote on June 23 believe it's best the best way to control Britain's borders, which under E.U. rules have been opened to workers from other member nations.

The Brussels-based union has in recent years expanded to Eastern European nations, and residents from the those countries have flooded the U.K., population 64 million, newly released data shows. That's stoked fears that the its traditions and values are changing. Others say the influx of outside residents keeps Britain's economy relatively strong.

The U.K.'s Office for National Statistics tracks the ebb and flow of people each year. I've charted the figures ahead of the vote.

The number of Britons, for example, returning home has remained relatively flat over the years, while the influx of those born elsewhere — both within and outside the union — has outpaced the natives:

Britons are also leaving in greater numbers than those returning to their home countries:

That led net migration — the number of all people leaving the country minus those arriving — to reach 330,000 last year, a peak after a particularly shape climb recently. This chart shows the trend over the years:

These immigration trends have significantly changed the number (and the nationality) of foreign-born residents in the U.K. This table shows the percentage increase in foreign-born residents from 2004, when Poland joined the E.U., to 2014. Check out Eastern Europe: