The FTSE-100 Index is made up of 100 companies. They are across many sectors, but what are these sectors, and what are the percentages of these sectors that make up the FTSE-100 ?

Oil & Gas Producers — 16.40%
Oil Equipment, Services & Distribution — 0.34%
Chemicals — 0.50%
Industrial Metals & Mining — 0.03%
Mining — 6.11%
Aerospace & Defence — 2.20%
General Industrials — 0.52%
Industrial Engineering — 0.68%
Support Services — 1.83%
Automobiles & Parts — 0.27%
Beverages — 4.84%
Food Producers — 2.60%
Household Goods & Home Construction — 1.76%
Personal Goods — 0.34%
Tobacco — 5.48%
Health Care Equipment & Services — 0.39%
Pharmaceuticals & Biotechnology — 7.20%
Food & Drug Retailers — 2.42%
General Retailers — 1.24%
Media — 1.83%
Travel & Leisure — 2.21%
Fixed Line Telecommunications — 1.27% [BT plc the only company]
Mobile Telecommunications — 5.59% [Vodafone plc the only company]
Electricity — 0.90%
Gas, Water & Multi-utilities — 3.44%
Banks — 13.45%
Nonlife Insurance — 0.38%
Life Insurance — 3.99%
Real Estate Investment Trusts — 0.94%
Financial Services — 0.65%
Software & Computer Services — 0.24%
Technology Hardware & Equipment — 0.82%
Oil Equipment, Services & Distribution — 0.21%
Mining — 2.09%
Support Services — 1.17%
Pharmaceuticals & Biotechnology — 0.62%
Media — 0.81%
Life Insurance — 0.21%
Construction & Materials — 0.58%
Travel & Leisure — 0.28%

The two biggest sector is Oil & Gas at 16.4% & Banks at 13.45%.

Interesting to see that BT Group PLC is 1.27% of the FTSE-100 and Vodafone PLC is 5.59% of the FTSE-100.