Input: There is a 50% decrease in the input value from 3000000 to 1500000. To calculate the percentage change, we need to use the following formula:

Percentage change = (New value - Old value) / Old value x 100%

In this case, the new value is 1500000 and the old value is 3000000. So, we can plug these values into the formula:

Percentage change = (1500000 - 3000000) / 3000000 x 100%

Percentage change = -50%

The negative sign indicates a decrease in value. Therefore, we can conclude that there is a 50% decrease in the input value from 3000000 to 1500000.

To summarize, the percentage change from 3000000 to 1500000 is a 50% decrease. This can be calculated using the formula (New value - Old value) / Old value x 100%.