เปอร์เซ็นต์ของผู้ใช้ที่ใช้ Netscape ในช่วงที่ 21.67% ใช้ Firefox?ไม่จำเป็นต้องใช้ตารางทั้งหมด
What percentage of users were using Netscape during the period in which 21.67% were using Firefox?It is not neccessary to use all the tables.
 table_13301:  "Period" [ text]  "Firefox" [ text]  "Safari" [ text]  "Opera" [ text]  "Netscape" [ text] 
SELECT "Netscape" FROM table_13301 WHERE "Firefox" = '21.67%'