The following graphs are for inbound and outbound traffic at the ports of Los Angeles and Long Beach in TEUs (TEUs: 20-foot equivalent units or 20-foot-long cargo container).
To remove the strong seasonal component for inbound traffic, the first graph shows the rolling 12 month average.
On a rolling 12 month basis, inbound traffic was up 0.2% compared to the rolling 12 months ending in April. Outbound traffic was down 0.4 compared to 12 months ending in April.
The downturn in exports in 2015 was probably due to the slowdown in China and the stronger dollar. Now exports are picking up again,
The 2nd graph is the monthly data (with a strong seasonal pattern for imports).
In general both exports and imports have been increasing.