The pie charts illustrate The proportion of 
pollutatns
 which entered Correct your spelling
pollutants
pollutant
in 
specific parts of Change preposition
apply
ocean
 from 7 Add an article
the ocean
diffrent
 Correct your spelling
different
source
, air, litter, farm waste, industrial waste, marine, offshore oil, Change to a plural noun
sources
domestic
 sewage, in 1997 and 2007. 
Correct word choice
and domestic
Overall
,  It can be seen that the Most Linking Words
pullutants
 came from air in both years. It stayed Correct your spelling
pollutants
steadily
 over Change the word
steady
the 
time, accounting for around 30 Correct article usage
apply
Use synonyms
percent
. It followed by the portion of marine trash in 1997, Change the spelling
per cent
while
 the rate of domestic sewage followed pollutants from Linking Words
air
 in 2007. 
Looking at the graph more closely, Add an article
the air
It is clear that
 the domestic sewage and offshore oil increased over the year compared to litter and marine rubbish decreased slightly over the period. Linking Words
Besides
, The rate of Linking Words
Industial
 waste dropped dramatically from 17 Correct your spelling
Industrial
Use synonyms
percent
 in 1997 to  9 Change the spelling
per cent
Use synonyms
percent
 in  2007. It Change the spelling
per cent
cut
 Add a missing verb
was cut
by
 halves throughout the period. Change preposition
in
Moreover
, Linking Words
Other
 notable feature is the percentage of litter rubbish in 2007, reporting 0 Change the wording
Another
Use synonyms
percent
.Change the spelling
per cent