Calculating Sums year to date

hi guys, new to the forum and hoping I can call on your expertise.

Basically trying to construct a formula which calculates a running YTD (Year to date) value.

I've attached the file example, layout as follows:
Column A contains commodities (e.g. coal, wood, rocks)
Columns B-M contains months Jan - Dec
Column N contains the YTD value (i.e. if current month = Jun then YTD would = sum of Jan - Jun)

Im thinking maybe something like a match formula? I've been playing around but just haven't managed to crack it.

Many thanks
Neill