There will/would be an upward trend with yearly sales rising from just below 150,000 in 2010 to 400,000 units in 2020, although a slight decrease is predicted to emerge in the year 2013 and 2018.
Setanta wrote: Using "would" completely alters the meaning of the sentence, and makes it an incomplete sentence, as this sentence does not describe the condition necessary to account for the financial performance.
Using 'would' COULD alter the meaning of the sentence but it doesn't necessarily do so, Jinmin. It also can show what you've suggested, "a kind of guess", a greater doubt on the part of the speaker/writer.
Using 'would' could even be illustrating a deontic [social modal meaning]. By using a modal of greater doubt, would
, the speaker/writer could just be showing a greater deference, allowing that his/her ideas are not the be all the end all.
Setanta wrote: ... and makes it an incomplete sentence, as this sentence does not describe the condition necessary to account for the financial performance.
Using 'would' does not make it an incomplete sentence. There is no need, NONE whatsoever, for the "condition" to be included in the same sentence.