The graph provides a comparison of fuel production levels in the UK between 1981 and 2000. 
Overall
, Linking Words
Petroleum
 has the highest Use synonyms
level
 of production in the timeframe, Use synonyms
whereas
 coal and natural Linking Words
gas
 see a fluctuating Use synonyms
level
 Use synonyms
subsequently
.
In 1981, Linking Words
petroleum
 and coal started production with roughly 100 Use synonyms
million
 Use synonyms
tonnes
 of power heat, Use synonyms
while
 natural Linking Words
gas
 Use synonyms
initially
 with under 50 Linking Words
million
 Use synonyms
tonnes
 in that particular year. Four years in period, Use synonyms
petroleum
 rose dramatically to 140 Use synonyms
tonnes
 and settled for 5 years before declining excessively to 100 Use synonyms
million
 Use synonyms
tonnes
 of energy units in 1991. Use synonyms
Moreover
,  in 1984, Coal declined by roughly under 50 Linking Words
million
 Use synonyms
tonnes
, Use synonyms
while
 natural Linking Words
gas
 remained steady from the initial year. 
In 1991, Use synonyms
although
 natural Linking Words
gas
 climbed significantly to 100 Use synonyms
million
 Use synonyms
tonnes
 till the end of the timespan, coal showed a notable decrease to lower than 40 Use synonyms
million
 Use synonyms
tonnes
 Use synonyms
level
, Use synonyms
additionally
, Linking Words
petroleum
 enlarged the Use synonyms
level
 to 140 Use synonyms
million
 Use synonyms
tonnes
 Use synonyms
at the end
 of the year.Linking Words