How to calculate market growth and market share?

Dear all,
I have access to a huge database in excel that involves sales data. The database is catagorized like:
Column A = Country
Column B = Product
Column C = Company
Column D = (Product) category
Column E = Sales
Column F = Period
Column G = Sales of particular company
Column H = Market category

Further details: see attached file!

I am looking for way to express developments (absolute and relative) in market growth and market share over time.

I have 3 questions:
How can i show the growth of the total market sales over time (period 1 to 4)?
How can i show the growth of the Int comapny sales over time (period 1 to 4)?
How can i show the market share of the Int company over time (period 1 to 4)?

Market growth can be calculated by comparing the sales amounts of the total market (or the Int company) to previous periods. Market share can be calculated by expressing the sales figures of the Int company in percentage of the total sales in a partical period (i=1,2,3,4).

If someone knows more about this matter please contact me. Thanks!
Greetings,
Kees