仅高手来试

total water quantity of these three is approximately 0.77% of that of the earth.

summation of the three occupies 0.77 persent of total water on the earth.

Summation of the three occupies 0.77 persent of total water on the earth.

The total of these three factors add up to 0.77% of the earth's total water content.

爽~

the total of these three account for (occupy) 0.77 percent of all the water on the earth.