A convoluted way of doing it, using existing skills and integrations. I am currently doing something similar as a simple calorie tracker. It is a real fudge, but it is working. The only difference for me is that I am using Integromat, rather than IFTTT, but the principle is the same.
1. Install Tweet It skill. This lets you say things to Alexa, and the result is tweeted. If you do not want to use your existing twitter account (if you have one), simply register a new one for this use alone.
1a. You can either say "Alexa, ask Tweet It <content>" or simply say "Alexa, ask Tweet It" and wait for Alexa to respond with "What should I tweet on your timeline". Although it takes a little longer, I find the second is more reliable.
1b. You want to keep your content simple as possible, to avoid having to parse a tweet. I would suggest you just say the number. Also, it is better to say "2 3 2" (i.e. "two three two") than "two hundred and thirty two". This is because Alexa will sometimes parse the latter as "232" (good) or "Two hundred and 32" (bad). Saying individual digits always gives you the right result. (Note that when you say "232", Alexa *will* reply "two hundred and thirty two. Is that right? It is - Alexa will write "232" to Twitter.
2. Then use your IFTTT account to read the tweets as they are written, and write them to your spreadsheet, along with a date/time stamp as appropriate.