Explanation:
I assume you mean
y = 28(1.01)^x
if I multiply something by a number that is even slightly larger than 1, the result will be bigger than the original "something" (except for 0, of course. where the result will be 0 again).
if I multiply by a number between 0 and 1, then the result will be smaller.
so, with growing x y will also grow.
and with every increase of x by 1 we multiply the previous result by 1.01.
1 represents 100%.
0.01 represents 1/100 of 100% = 1%
1.01 = 100% + 1%
the the percentage rate of increase is 1%.