These differences are exacerbated by the long time lag between when applications are filed and patents are granted.

由于专利从申请到批准，需要很长一段时间，所以目前这两家的专利数差距还会进一步拉大。

youdao

It is difficult to determine an exact number because of a lag time in official counts and differences in the states' standards.

CNN: Northwest heat endangers crops