Used stamps exchanges.

I decided to calculate to which country the letters are not delivered well. To do this, I took the top 100 members and copied the table into excel file, then divided the number of letters sent by the number of letters received for each user and finally sorted by this value.
If all the letters were delivered without losses, then for a user with a high rating and a large number of sent letters this value would be approximately 1/1,125 = 0,89 . And the more undelivered letters are, the larger this number is.
I got that New Zealand mail works best - Feijoa_girl has a coefficient = 0.91. And the worst with mail delivery is in Belgium - rajen has a coefficient = 1.32.
If we take first and last 10 values of these coefficients, the best ones are New Zealand, Finland, Sweden, Iceland, Germany, Netherlands, Norway, Spain, France and Italy. Many undelivered letters from users are in Belgium, Russia (twice), Latvia, China (three times), USA (twice) and Italy.
These are the statistics of our club.

N User Sent Rec. Sent/Rec.
1 rajen (Belgium) 83 63 1,3175
2 Olga (Russia) 97 83 1,1687
3 flax600 (Latvia) 91 78 1,1667
4 luosida (China) 145 128 1,1328
5 trainfanaticn (USA) 86 76 1,1316
6 galasekk (Italy) 103 92 1,1196
7 littleeling (China) 115 104 1,1058
8 ismx (Russia) 187 170 1,1
9 Luofei (China) 143 130 1,1
10 pinkpolarbear (USA) 116 106 1,0943
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------------------
90 pirkko (Finland) 408 433 0,9423
91 franxx74 (Italy) 97 103 0,9418
92 nelliegirl (France) 94 100 0,94
93 egp1 (Spain) 379 404 0,9381
94 Erling (Norway) 233 249 0,9357
95 Marleen1979 (Neth.) 213 228 0,9342
96 stex (Germany) 94 101 0,9307
97 Sveinn (Iceland) 102 110 0,9273
98 GLund (Sweden) 103 112 0,9196
99 pete (Finland) 170 185 0,9189
100 Feijoa_girl (N.Z.) 112 123 0,9106

Natalia, you are missing one topic on your statistic study. At the beginning of this club, the initial members received extra slots to accommodate for enough club free slots to allow initial exchanges ... Thus some of these users still have more received than sent exchanges (eg. me, although I've now lost 4 exchange packs I still have a positive ratio of 2).

Oh oh, I just 'drew' an exchange partner in Slovenia and filled the envelope ;-)
Still sending it of course, the joy of (him/her) someone receiving a package outweighs the disappointment (me) of knowing they got lost.

a lot of lost mail is in time lapse of march2020 - may2020 due to Corona situation...

It is especially interesting when the club members from the same country are at opposite poles of this table ... :)

Interesting statistics. I checked my results and it was 0,95 (266/280). But there might be several reasons for this difference. My opinion is that sometimes you get addresses to collectors who have already stopped being active. They receive the letters, but do not register them. But it is also correct that now and then yoy get an address With a profile that you regret asking for. And sometimes the mail system is to blame.

After nine months

N User Sent Rec. Sent/Rec.
1 rajen (Netherlands) 99 79 1,25
2 flax600 (Latvia) 97 80 1,21
3 Javierstamps (Chile) 124 106 1,17
4 luosida (China) 193 174 1,11
5 branoham (Slovakia) 195 177 1,10
6 laurent (France) 135 123 1,10
7 trainfanatic (USA) 92 84 1,10
8 dadika30. (Slovenia) 252 232 1,09
9 Luofei (China) 184 170 1,08
10 crazystamper (USA) 129 120 1,08
--------------------
--------------------
91 wuff67 (Austria) 328 348 0,94
92 pirkko (Finland) 438 466 0,94
93 egp1 (Spain) 399 425 0,94
94 tantoo (France) 90 96 0,94
95 timar (Finland) 90 96 0,94
96 nelliegirl (France) 102 109 0,94
97 trebuh (Canada) 116 125 0,93
98 GLund (Sweden) 103 112 0,92
99 franxx74 (Italy) 110 120 0,92
100 Feijoa_girl (N.Z.) 115 126 0,91

The letters are delivered well to New Zealand, Italy, Sweden, Canada, France, Finland, Spain and Austria.
The letters are delivered badly to Belgium, Latvia, Chile, China, Slovakia, France, Slovenia and USA.

After two weeks there are some changes in the above table:

1 flax600 Latvia 92 78 1,1795
2 Olga Russia 99 85 1,1647
3 trainfanatic USA 87 77 1,1299
4 boka Israel 130 116 1,1207
5 galasekk Italy 103 92 1,1196
6 Javierstamps Chile 102 92 1,1087
7 luosida China 146 132 1,1061
8 littleeling China 116 106 1,0943
9 KLM04889 Netherlands 165 151 1,0927
10 pinkpolarbear USA 118 108 1,0926
----------------------
----------------------
91 khamus Israel 113 120 0,9417
92 egp1 Spain 380 405 0,9383
93 Erling Norway 233 249 0,9357
94 Feijoa_girl N.Z. 115 123 0,935
95 Marleen1979 Netherlands 213 228 0,9342
96 nelliegirl France 94 101 0,9307
97 stex Germany 94 101 0,9307
83 GPKnl Netherlands 92 99 0,9293
98 Sveinn Iceland 102 110 0,9273
99 GLund Sweden 103 112 0,9196
100 pete Finland 170 185 0,9189

"Tempus spargendi lapides et tempus colligendi..."
Some members left out the top100 and they are no longer in the table (rajen, Belgium).
The letters are delivered well to Finland, Sweden, Iceland, Netherlands, Germany, France, New Zealand and Israel.
The letters are delivered badly to Latvia, Russia, USA, Israel, Italy, Chile, China and Netherlands.
Please note that 2 countries - the Netherlands (KLM04889 and GPKnl) and Israel (boka and khamus) - there are on both lists. Compare the wishes of these users. Perhaps, due to so high requirements/wishes of someones they don't receive letters? :)

I have 12 letter that never arrived at their destination, one of then it did but the recipient didn't know how to register it, that's what he told me, in all most of them are for different countries except two for Canada, two for Croatia and two for Belgium.

this is statistic for this club

i have my own stats for my exchanges thru the years and i have to say - most letters i have lost to Italian and Russian addresses (if i look my club expired (if i take them as lost) ones - above all are the USA)

No body's crazy here but hoping for something bad to happen is not a very positive thought.

What about mental health of some?? :):):)

I hope not!

I hope so....

Wolfgang, I suggest that all the members of this club are honest people :)

Thanks a lot , Natalia :)
But there is one unsave subject in your calculation.
e.g. You get a slot for sending a letter, but you can never be sure if this letter was really sent.

Gran trabajo;):)
Great work
Bravo !!!!!!

Thank you for doing this. Makes for a very interesting read.