The Iron Dome missile defense system has achieved a nearly 90 percent success rate since Monday night, an improvement over its performance during Operation Pillar of Defense in November 2012.

The defense system is activated only when the rockets fired by Palestinian militants at Israel appear likely to hit populated areas.

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WATCH: Iron Dome intercepts rockets across Israel

It has been activated to intercept about 27 percent of the approximately 180 rockets fired between Monday night and midday Wednesday. Of the times when Iron Dome was activated, it successfully intercepted the rockets nearly 90 percent of the time, and there have been few rocket hits or serious injuries.

The success of the defense system marks an improvement over the 84 percent success rate during Operation Pillar of Defense.

The comparison is not exact, however, especially given that Iron Dome had a slightly higher success rate at the beginning of the 2012 operation as well.

A senior Israel Defense Forces officer said Wednesday that the number of rockets to hit Israel can be expected to rise.

The army has made significant improvements to the Iron Dome batteries over the past two years that have made them better able to intercept rockets and to cope with rocket barrages, the army said.

Israel's seven Iron Dome batteries have been deployed across the country to protect populated areas from short-range rockets, with the assistance of the David's Sling missile defense system, which is designed to shoot down missiles with ranges of between 100 kilometers and 200 kilometers. Though the David's Sling system, sometimes called Magic Wand, is still under development, it has been integrated into one of the Iron Dome batteries.

Meanwhile, there have been some changes to civilian aviation, including takeoff and landing paths, because Hamas is aiming some of its rockets at Ben-Gurion International Airport, about 80 kilometers from Gaza. This has also affected flight schedules, which have been spread out over more hours rather than clustered together.