In this task, you're given a passage, further information available on a particular linked term from the statement, and a question. Your job is to generate the answer to the question by using the information provided. If there is no clear answer obtainable, output 'none'.
Q: Passage: German Type IXB submarines were slightly larger than the original German Type IX submarines, later designated IXA. U-109 had a displacement of when at the surface and while submerged. The U-boat had a total length of , a pressure hull length of , a beam of , a height of , and a draught of . The submarine was powered by two MAN M 9 V 40/46 supercharged four-stroke, nine-cylinder diesel engines producing a total of for use while surfaced, two Siemens-Schuckert 2 GU 345/34 double-acting electric motors producing a total of for use while submerged. She had two shafts and two propellers. The boat was capable of operating at depths of up to .
Link Information:

The German Type IXB submarine was a sub-class of the German Type IX submarine built for Nazi Germany's Kriegsmarine between 1938 and 1940. Question: How much before the IXB submarines came out did the IX submarines come out?
A:
Answer: 1