SAN FRANCISCO (Reuters) - Apple Inc forecast its first revenue drop in 13 years and reported the slowest-ever increase in iPhone shipments as the critical Chinese market showed signs of weakening, suggesting the technology company's period of exponential growth may be ending.

The slowdown comes as Wall Street analysts worry the company does not have another blockbuster product to replace the iPhone. Apple does not report Watch sales, but it does not appear to have the makings of being a hit on the same level as the iPhone a year after launch.

And while the company is reportedly working on a car, what it plans to do in that area and when are still unclear.