On the surface at least, China’s economy grew at a respectable 7 percent in the second quarter, beating expectations and right on track for the government’s annual growth target. When GDP is unadjusted for price changes — known as nominal GDP — growth is running 2 percentage points weaker than last year, according to data compiled by Bloomberg. One reason being touted to explain the gap is that China miscalculates the so-called GDP deflator, a broad measure of prices in the economy.