GDP measures the growth of the economy as a whole, over time, within a particular geographical area.
If you say that share of GDP of a certain industry to nationwide GDP has changed from 28% to 12%, but overall GDP grew 600% (or whatever), then mathematically, said industry grew -- it wasn't #1 in growth, but it still grew.
Nor does manufacturing need to be #1. The service sector can grow without sucking up other industry's resources, so naturally the GDP-share of other industry is going to shrink.
These are well-defined terms in economics. You're just being obtuse.