Arduino code idea to leave run duration log in EEPROM. (not tested)

run_log.ino

#include <EEPROM.h>
#define CLEAR_BUTTON (2)
#define MAX_LOG_N (120)

struct run_log_t {
    uint8_t last_index;
    uint16_t duration[MAX_LOG_N];
};

uint8_t index;
bool is_full = false;
run_log_t run_log;

void setup() {
    if ( digitalRead(CLEAR_BUTTON) ) {
        memset(&run_log, 0xff, sizeof(run_log));
        EEPROM.put(0, run_log);
    }
    EEPROM.get(0, run_log);
    if (run_log.last_index == 0xff) { // not initialized
        index = 0;
    } else if (run_log.last_index == MAX_LOG_N) {
        is_full = true;
    } else if (run_log.last_index < MAX_LOG_N) {
        index = run_log.last_index + 1;
    } else { // invalid
        is_full = true;
    }
    if (!is_full) {
        run_log.last_index = index;
        run_log.duration[index] = 0;
    }
}

void loop() {
    // update duration per step time (like 1 min.)
    #define LOG_STEP (60000) // [ms]
    if (!is_full) {
        static unsigned long t1 = LOG_STEP;
        if (millis() > t1) {
            t1 += LOG_STEP;
            run_log.duration[index] ++;
            EEPROM.put(0, run_log);
        }
    }
}